Environmentally Friendly Colorant Compositions and Latex Paints/Coatings

ABSTRACT

The invention relates to colorant compositions, and aqueous latex paints or other water-borne coatings made from them, which have a mitigated environmental impact. Levels of solvents, additives and impurities comprising volatile non-aqueous constituents, alkylphenol ethoxylates (and derivatives thereof), crystalline silica, and/or formaldehyde are decreased relative to those typical of preceding generations of colorants and tinted aqueous latex paints and other water-borne coatings. On the other hand, paint-performance as indicated by any of Stormer viscosity stabilization, rheological profile flow/leveling and sag resistance, water sensitivity and color transfer resistance is comparable to a paint in which the aforementioned solvents, additives and impurities are still present.

FIELD OF THE INVENTION

The invention relates to colorant compositions, and aqueous latex paintsor other water-borne coatings made from them, which have a mitigatedenvironmental impact.

BACKGROUND OF THE INVENTION

There is increasing societal sensitivity to environmental issues,including minimization of solvent and impurity levels for the purposesof eliminating health concerns, preserving the integrity of the earth'sresources, and the like. In that connection, there have been substantialefforts not only in the public sector, but also the private sector, toinstitute improved environmental practices. This has included theintroduction of voluntary and sometimes mandatory standards by which theenvironmental friendliness of products and services in the marketplacecan be judged (see Green Seal Environmental Leadership Standard forPaint GS-11). Products and services which meet such standards, and thecommitment to furnishing same, are often referred to as “green”. Indeed,it is considered very valuable to be qualified to apply the designation“green” (or some equivalent) to products and services in commerce.

One area in which the foregoing has become important is construction andrenovation products, and especially aqueous latex paints and otherwater-borne coatings. There are governmental regulations for mandatingthe environmental friendliness of such paints and other coatings, buttypically non-governmental third-party standards are even more rigorous.Examples of the latter standards are LEED, GREENGARD, GREENGARD Childrenand Schools, MPI Green Performance, Green Seal, and Collaborative forHigh Performance Schools. Pursuant to standards such as these, levels ofsolvents and impurities such as volatile non-aqueous constituents(sometimes referred to in this specification as “VNCs”), alkylphenolethoxylates (sometimes referred to in this specification as “APES”),crystalline silica, and formaldehyde are controlled.

However, simply minimizing the amount of environmentally undesirablesubstances in paints and other coatings is recognized to beinsufficient. Instead, the “greening” of paints and other coatings wouldpreferably be achieved without undue loss of performance in providingprotection for surfaces which they are utilized to cover. For instance,the MPI Green Performance standard “therefore requires that all productsshall meet or exceed the performance requirements of the applicable MPIproduct standard.” The point is that “greening” should, to the extentpossible, not entail sacrificing properties which are conventionallytaken as characterizing proper paint performance.

Achieving the dual objectives of “greening” paints and other coatingswhile maintaining good performance is a challenging proposition. We haveseen that formulating aqueous latex paints and other water-bornecoatings in accordance with “green” principles commonly leads todegradation of at least one important property, and often more than one,in the paint or other coating in question. More specifically, in ourexperience paint/coating performance can be characterized by: Stormerviscosity stability; rheological profile; flow/leveling and sagresistance; water sensitivity; and color transfer resistance. When anaqueous latex paint or other water-borne coating is “greened” byminimization of solvent, additive or impurity content such as VNCs, APEsor derivatives, crystalline silica and formaldehyde, it is clearlydifficult to prevent the diminution of one or more of those properties.

Further complication arises when aqueous latex paints or otherwater-borne coatings are tinted. The tinting process is often carriedout by means of adding one or more colorant compositions at the point ofsale to a pre-formulated base composition. This is a popular andadvantageous way of marketing tinted paints or other coatings,especially tinted aqueous latex paints. However, unlike pre-formulatedaqueous latex paints and other water-borne coatings, colorantcompositions are not generally included within the scope of materialsgoverned by “green” standards (at least non-governmental third-partystandards). By way of example, see the MPI Green Performance standardrelating to VOLATILE ORGANIC COMPOUND (VOC) REQUIREMENTS, wherein it isprescribed that the “calculation of VOC shall exclude water and tintingcolor added at the point of sale”, as well as the GS-11 standard whereinit is stated “Low- or zero-VOC paints have experienced increased sales,but many shoppers are not aware that VOC levels may increase with theaddition of colorants to the base paint.” It follows that addition ofcolorant compositions which are not conformed to “green” standards canlead to a “back door” introduction of environmentally undesirablesolvents, additives and impurities that undercuts any advantageotherwise gained by “greening” the pre-formulated base compositions.Accordingly, it would be a substantial advance if there were providedaqueous latex paints and other water-borne coatings which qualify forthe designation “green” but retain their high performancecharacteristics, and at the threshold a colorant composition capable ofyielding such paints and other coatings.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the invention to provide acolorant composition capable of yielding an aqueous latex paint or otherwater-borne coating with mitigated environmental impact, and(correspondingly) a paint or other coating which exhibits such mitigatedimpact.

It is another object of the invention to provide a colorant compositioncapable of yielding an aqueous latex paint or other water-borne coatingwith mitigated environmental impact as a result of decreased amounts ofsolvents, additives or impurities such as VNCs, APEs and derivativesthereof, crystalline silica and formaldehyde, and correspondingly anaqueous latex paint or other water-borne coating having decreasedamounts of those solvents, additives or impurities.

It is an additional object of the invention to provide a colorantcomposition and paint or other coating as aforesaid, which furtherenable the achievement of performance comparable to paints or coatingsin which the levels of VNCs, APEs and derivatives, crystalline silicaand formaldehyde have not been lowered for environmental advantage.

It is yet another object of the invention to provide a colorantcomposition and paint or other coating as aforesaid in which Stormerlow-shear viscosity stability, rheological profile, flow/leveling andsag resistance, water sensitivity, and color transfer resistance arecomparable to those properties as exhibited by aqueous latex paints orother water-borne coatings unmodified to address environmental concerns.

And, it is still another object of the invention to provide methods ofmaking such colorant compositions and paints or other coatings.

These and other objects are attained through practice of the inventionas follows:

In one aspect, the invention is in a colorant composition suitable as aprecursor to an aqueous latex paint or other water-borne coating, whichcolorant composition comprises at least one pigment, water, and acopolymer surfactant, which colorant composition is not itself anaqueous latex paint or other water-borne coating. The copolymersurfactant comprises moieties corresponding to the following monomers

(a) from about 10% to about 80% by weight of at least one C₃-C₁₂α,β-ethylenically unsaturated carboxylic acid or anhydride,

(b) from about 10% to about 80% by weight of at least one C₃-C₁₂α,β-ethylenically unsaturated vinyl monomer, and

(c) from about 0.01% to about 20% by weight of at least one surfactantmonomer, wherein each said surfactant monomer is either an acrylic ormethacrylic ester moiety joined with a hydrophobic moiety by a bridginggroup comprising a poly(ethyleneoxy) moiety. The colorant composition issubstantially free of, collectively: any volatile non-aqueousconstituents; any alkylphenol ethoxylates or derivatives thereof; anycrystalline silica; and any formaldehyde. Nevertheless, the colorantcomposition is capable of (i) mitigating any change in the Stormerlow-shear viscosity of an aqueous latex paint or other water-bornecoating formed of a mixture comprising said composition and a tint base,such that said Stormer low-shear viscosity of said paint is notsubstantially changed compared with the Stormer low-shear viscosity ofthe tint base, and (ii) yielding such paint or other coating which alsoexhibits flow/leveling and sag of at least 8, water sensitivity of atleast 3, and color transfer of at least 3.

In another aspect, the invention is in an aqueous latex paint or otherwater-borne coating which comprises a mixture of a tint base andcolorant composition containing at least one pigment, water and acopolymer surfactant comprising moieties corresponding to the followingmonomers:

(a) from about 10% to about 80% by weight of at least one C₃-C₁₂α,β-ethylenically unsaturated carboxylic acid or anhydride,

(b) from about 10% to about 80% by weight of at least one C₂-C₁₂α,β-ethylenically unsaturated vinyl monomer, and

(c) from about 0.01% to about 20% by weight of at least one surfactantmonomer, wherein each said surfactant monomer is either an acrylic ormethacrylic ester moiety joined with a hydrophobic moiety by a bridginggroup comprising a poly(ethyleneoxy) moiety. The paint or other coatingis substantially free of, collectively: any volatile non-aqueousconstituents; any alkylphenol ethoxylates or derivatives thereof; anycrystalline silica; and any formaldehyde. Despite that, (i) the Stormerlow-shear viscosity of said paint, its formation by mixing of thecolorant composition with the tint base notwithstanding, is notsubstantially changed compared with the Stormer low-shear viscosity ofthe tint base, (ii) flow/leveling and sag are at least 8, (iii) watersensitivity is at least 3, and (iv) color transfer is at least 3.

In a further aspect, the invention is in a method of making a colorantcomposition suitable as a precursor to an aqueous latex paint or otherwater-borne coating, which comprises combining the components water, atleast one pigment, and an aforementioned copolymer surfactant, whereinthe amount of any VNCs, APEs or derivatives thereof, crystalline silicaand formaldehyde incident to the incorporation of such components is asdisclosed previously for the colorant composition of our invention.

In an additional aspect, the invention is in a method of making anaqueous latex paint or other water-borne coating, which comprisescombining a tint base as disclosed above and a colorant composition asdisclosed above, such that the amount in the paint or other coating ofany VNCs, APEs or derivatives thereof, crystalline silica is asdisclosed previously herein for the paint or other coating of ourinvention.

Practice of the invention confers substantial advantages. Morespecifically, with the invention not only are VNCs reduced to anexceedingly low level or effectively eliminated, but also such reductionor elimination is also true in respect of APEs and derivatives thereof,crystalline silica and formaldehyde (these are sometimes referred to inthis specification as “target substances”). As a consequence, theaqueous latex paint or other water-borne coating produced in accordancewith the invention meets the requirements of numerous differentgovernment and industry standards for environmental friendliness. Thisis significant because it can lead to an entitlement to designate paintsof the invention as “green” and/or free of various undesirablematerials, in accordance with various standards referred to in thepreceeding “Background” section, as well as in accordance with the EPA'sdefinition of Hazardous Air Pollutants (“HAPS”), as constituted as ofthe filing date of this disclosure. Furthermore, there has not to ourknowledge been a colorant composition prior to the invention produced insuch manner that any amounts of solvents, additives and/or impuritieswhich interfere with environmentally responsible paint formulation,i.e., VNCs, APEs or derivatives thereof, crystalline silica, andformaldehyde, are held at an acceptably low level. With the invention,the customary carry-through effect on a product paint or coating of suchsolvents, additives and impurities in a colorant composition from whichthe paint or other coating is made can be lessened or completely removedas a factor, because the colorant composition of the invention itselfmeets (or at least is such that a paint or other coating formulated withit meets) the aforementioned standards, and thus it also can often bedesignated “green” or free of various undesirable materials inaccordance with those standards and/or HAPS (as constituted as of thefiling date of this disclosure). However—and this is integral to ourinvention—the mitigation of environmentally undesirable effects is notaccompanied by an appreciable fall-off of any of the good performancecharacteristics already identified by us, namely: Stormer low-shearviscosity stability; rheological profile, flow/leveling and sagresistance; water sensitivity; and color transfer resistance. Rather, astrong performance contour is maintained in respect of those propertiescollectively. This means that improvement on the environmental front isachieved without materially degrading performance as to any of the keyproperties discussed previously, which is contrary to what ourexperience suggested and therefore would have been unexpected bypractitioners in the field at the time of our invention.

At the threshold, it is important for an understanding of the inventionto recognize differences between and among three fundamental anddistinct concepts in the technological area of interest namely, aqueouslatex paints and other water-borne coatings, colorant compositions whichare utilized to tint such paints and coatings, and tint bases with whichthe colorant compositions are combined in formulating such paints andcoatings. Thus, an aqueous latex paint or other water-borne coating istypically air-dried and ordinarily comprises water, a film-formingpolymeric binder in sufficient amount to form a paint film or coatingupon drying, one or more pigments, and various additives such asassociative thickeners. In contrast, a colorant composition is not apaint or other coating as aforesaid, but rather a water-based andtypically concentrated dispersion of a relatively large volume ofpigment in a relatively small volume of water; other components aregenerally also be present, in particular one or more surfactants tofacilitate dispersion of the pigment content. Unlike such paint or othercoating, a colorant composition does not contain an amount offilm-forming polymeric binder sufficient to form a film upon drying.And, a tint base is neither a paint/coating nor a colorant composition,but rather a precursor component of a paint/coating which containswater, a film-forming polymeric binder in sufficient amount to provide afilm upon drying of a paint/coating made with such tint base, and whiteor pastel pigmentation to furnish an essentially neutral foundation fortinting with a colorant composition. The tint base contributes to thehiding power of a paint, but does not contain pigment suitable to serveas the tinting agent for a final paint or coating, and is neither apaint/coating nor colorant composition. For purposes of the instantpresentation, the terms “aqueous latex paint”, “water-borne coating”,“colorant composition”, and “tint base” shall be interpreted inaccordance with the meanings indicated in the preceding sentences ofthis paragraph and the other portions of this specification asappropriate.

As used in this specification, a “polymer” is a compound comprising oneor more different component units, each such component unit being amoiety corresponding to a particular monomer. A “copolymer” is a polymercomprising at least two different component units, each of which unitscorresponds to (and is derived from) a different monomer. Thus, acopolymer comprising component units corresponding to three differentmonomers (also known as a terpolymer) is included within the term“polymer,” as is a polymer comprising one component unit (also known asa homopolymer).

Similarly, in this specification, “VNC” or “volatile non-aqueousconstituent” means substances other than water which are released intothe environment from a colorant composition, or a paint or coating,under conditions to which such composition, paint or coating is normallyexposed. The terms encompass both organic (for instance, volatileorganic compounds or “VOCs”) and inorganic substances, and decompositionor other reaction products of precursor materials in the composition,paint or coating. It is noted that APEs and their derivatives are oftencategorized separately from VOCs and that distinction is observedherein, VNCs being deemed not to include APEs or derivatives thereof.

Further, in this specification, “substantially free” means (a) inrespect of a colorant composition, an amount no greater than about 0.3weight % and (b) in respect of an aqueous latex paint or otherwater-borne coating, or a tint base, an amount no greater than about0.15 weight %. Furthermore, in this specification the term“substantially entirely free” means an amount no greater than 0.0005weight %.

The disclosure of each of U.S. Provisional Application No. 60/496,366,filed Aug. 18, 2003, U.S. application Ser. No. 10/728,599 filed Dec. 4,2003 and U.S. Pat. No. 7,402,627 based thereon, U.S. application Ser.No. 11/193,131 filed Jul. 29, 2005, U.S. application Ser. No. 11/319,840filed Dec. 28, 2005, and U.S. application Ser. No. 12/177,071 filed Jul.21, 2008, is incorporated by reference in its entirety.

All concentrations and amounts disclosed in this specification are byweight unless indicated otherwise; concentrations and amounts indicatedas being no greater than a certain number are to be interpreted to meanfrom and including zero up to the stated concentration or amount.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

A central feature of our invention is the discovery of environmentallyfriendly, “green” colorant compositions, and aqueous latex paints aswell as other water-borne coatings, which enable the substantialmitigation of undesirable environmental effects attendant upon use ofcolorant compositions for tinting aqueous latex paint or otherwater-borne coatings, and the paints or other coatings made utilizingsuch compositions, with concomitant maintenance of high-levelperformance of such paints and other coatings in respect of Stormerlow-shear viscosity stability, rheological profile, flow/leveling andsag resistance, water sensitivity, and color transfer resistance. Incertain advantageous embodiments, blocking resistance and glossretention are additionally maintained at a high performance level. Theforegoing is achieved by the careful restriction of materials from whichthe colorant compositions and paints or other coatings of the inventionare formed solely to those that intrinsically—or as a consequence ofappropriate processing—do not entail the presence of VNCs, APEs orderivatives thereof, crystalline silica or formaldehyde. Unlikepreceding colorant compositions and aqueous latex paints or otherwater-borne coatings, our invention proceeds from the discovery that,contrary to conventional wisdom, it is not necessary to settle for onebut not the other of good purity and good properties. That is so say,while there would have seemed to be a fundamental tension betweenmitigating environmental disadvantages on the one hand, and preserving astrong performance contour on the other, that tension is resolvedthrough practice of the invention whereby both desiderata are enabled.The dual objectives are attainable with the realization that certainbeneficial combinations of components and processing measures obviatethe apparent dichotomy between addressing environmental concerns andachieving desirable colorant and paint/coating performance.

Thus, in the colorant compositions used for tinting aqueous latex paintsor other water-borne coatings the total amount of VNCs. APEs andderivatives thereof; crystalline silica, and formaldehyde present in theaggregate is not greater than 0.25 weight %, based on the weight of thecolorant composition. Further, any amount present of the aforementionedconstituents in the aggregate is preferably no greater than 0.15 weight%, and more preferably no greater than 0.1 weight %. Embodiments of thecolorant compositions which are substantially entirely or completelyfree of the aforementioned substances are most preferred.

In certain good embodiments of the inventive colorant composition: (i)the content of any VNCs is preferably no greater than 1000 ppm and morepreferably no greater than 300 ppm; (ii) the content of any APEs orderivates thereof is no greater than 1000 ppm and preferably no greaterthan 300; (iii) any content of crystalline silica is preferably nogreater than 100 ppm and more preferably no greater than 5 ppm; and (iv)any content of formaldehyde is preferably no greater than 10 ppm andmore preferably no greater than 5 ppm. Accordingly, the colorantcompositions, whether before or after incorporation in an aqueous latexpaint or other water-borne coating, do not have an appreciably negativeimpact on the environment.

In other good embodiments of the invention, the aqueous latex paint orother water-borne coating: (i) the content of any VNCs is preferably nogreater than 500 ppm and more preferably no greater than 300 ppm; (ii)the content of any APEs or derivatives thereof is preferably no greaterthan 100 ppm; (iii) the content of any crystalline silica is preferablyno greater than 100 ppm and more preferably no greater than 5 ppm; and(iv) the content of any formaldehyde is preferably no greater than 5ppm.

As indicated in a preceding passage of this disclosure, it is alsoadvantageous that a colorant composition of the invention be free—or atleast substantially free—of HAPS. Thus, in an alternative embodiment ofthe invention the colorant composition is substantially, and preferablysubstantially entirely, free of HAPS (as opposed to the targetsubstances per se, though there can be overlap). Likewise, in anotheralternative embodiment of the invention the aqueous latex paint or otherwater-borne coating is substantially, and preferably substantiallyentirely, free of HAPS (again, as opposed to the target substances perse, though there can be overlap).

The invention focuses on the reduction of a number of commonlyencountered but environmentally undesirable substances:

VNCs, often (but not exclusively) VOCs, are incorporated in manycomponents of a typical paint or coating, and colorant compositions toincrease flexibility as a result of enabling use of a wider variety ofcomponent materials, especially resins, as well as to improve open time,freeze-thaw stability, flow/leveling, and gloss development. Thus,coalescence solvents used to improve paint performance, freeze thawadditives to prevent freezing when shipping, surfactants for dispersingpigments and providing application properties, and defoamers, along withother additives, typically comprise some volatiles intrinsically orthrough incorporated solvents. Low or zero volatile versions of theseadditives generally exhibit poorer performance as compared tocounterparts with higher volatiles contents, and are more expensive.Replacement of these constituents is not trivial since all must bewater-soluble or water-dispersible, have good stability in water, andotherwise be compatible (and perform their intended functions incombination) with sometimes twenty or thirty other components of thecoating or colorant, and in many different product lines. Residualmonomers and impurities in latexes can also be volatiles. These arecommon by-products of the manufacture of these latexes. They are veryfrequently found in all latexes in small quantities unless expensive andtime consuming steps are taken to reduce their levels. Also, such stepshave been associated in the past with poor latex stability andperformance.

APEs and their derivatives are some of the most economical, bestperforming and widely used substances in the coatings industry. They arefound in latexes, rheology modifiers, defoamers, biocides, surfactantsand many other additives, and facilitate both incorporation into aformulation and performance enhancement. While there has been someinformation furnished to address the availability of substitutes for thevarious materials based on APES and derivatives thereof, this is generalin nature and based on intended uses, and not keyed to diminishing thecontent of APEs or derivatives thereof while still maintaining anacceptable performance contour. Achieving the latter still requiresextensive testing or other investigation, and innovative selection, tofind a suitable alternative substance or blend of substances. In manycases a comparable surfactant using alternative chemistry is notavailable.

Crystalline silica is found as a naturally occurring impurity in manyfillers commonly used to formulate paint or other coatings, and colorantcompositions. Most of the fillers used in paints, particularly flatpaints, and other coatings contain extender pigments that havecrystalline silica impurities. Forgoing use of materials containingcrystalline silica can sometimes contribute to degradation of final filmproperties.

Formaldehyde is introduced during paint and colorant formulation, mainlyas part of a formaldehyde releasing biocide or as an impurity.Formaldehyde releasing biocides are some of the most common, leastexpensive and most effective biocides used in coatings to preventspoilage of the product.

Mitigation of the presence of the aforementioned solvents, additives orimpurities is highly beneficial. VNCs can degrade the atmosphere whenreleased into it (see Green Seal GS-11 Standard). Moreover, some of themare typical and significant sources of residual odor associated withlatex consumer paints directly due to their incorporation as or as partof a coalescing solvent (for instance, 2,2,4-trimethylpentanediolmonoisobutyrate (Texanol)). (VNC levels can be determined via aheadspace gas chromatography/mass spectroscopy method as describedhereinafter.) Similarly, APES and derivatives thereof can also beharmful to the environment, particularly aquatic life, and thus areundesirable from an environmental standpoint. (APEs and derivativesthereof, such as nonyl phenol ethoxylates or octyl phenol ethoxylates,and derivatives thereof, can be determined, both qualitatively andquantitatively, using a UV spectrophotometer or LC-UVspectrophotometer.) Crystalline silica has been linked to a number ofhealth concerns (see Green Seal Crystalline Silica Clarification issuedSep. 25, 2009). And, formaldehyde also gives rise to health concernsconnected with its release into the environment from a colorantcomposition, or an aqueous latex paint or other water-borne coating,containing same.

Accordingly, the invention's efficacy in providing environmentallyfriendly products is apparent. However, the crux of the invention is notsimply that “greening” is achieved, but that “greening” is achieved inconcert with maintenance at a high level of the performance of aqueouslatex paints or other water-borne coatings made from such colorantcomposition. That is to say, with our invention the overall performancecontour is highly advantageous in that: (i) the viscosity stability ofthe paint vis-à-vis its precursor tint base is good, the paint's Stormerlow-shear viscosity not being substantially changed in comparison tothat of the tint base by addition of the colorant composition to thebase during paint formulation; (ii) the rheology profile, flow/levelingproperties and sag resistance, of the paint are good; (iii) the paint'swater-sensitivity is good; and (iv) the paint's color transferresistance (e.g., due to “rub-off”) is likewise good.

More specifically, copolymer surfactants incorporated pursuant to theinvention—which are substantially free of the previously identifiedsolvents, additives and impurities—interact with latex particles and/orwith associative rheology modifiers of a tint base or other aqueous (orwater-borne) dispersion (also substantially free of the previouslyidentified solvents and impurities), as well as of a latex paint orother water-borne coating in accordance with the invention. Thesecopolymer surfactants can associate beneficially with surfaces offilm-forming (e.g., latex) particles and with “bridging micelles” ofassociative thickeners. Without wishing to be bound by theory, it isthought that the presence of such copolymer surfactants does notsubstantially change the Stormer low-shear viscosity, and insteadsubstantially preserves the network structure of latex paints and otherwater-borne coatings. That is, colorant compositions of the presentinvention are such that, when incorporated in a paint or other coatingof the invention formed of a mixture comprising such a composition and atint base (i.e. aqueous latex base paint or other aqueous polymerdispersion), they do not result in a substantial change of the Stormerlow-shear viscosity of said paint/coating compared with the Stormerlow-shear viscosity of the tint base. Practice of the invention thusyields the desired mitigation of any substantial change in the Stormerlow-shear viscosity of the paint or other coating compared with theStormer low-shear viscosity of the tint base. In advantageousembodiments of the invention, the Stormer low-shear viscosity of a paintor other coating tinted with a colorant composition of the invention iswithin about ±20%, preferably ±15%, of the Stormer low-shear viscosityof the tint base from which the paint or other coating was formed. Aneven more preferred embodiment is one in which the low-shear viscosityof a paint or other coating tinted with a colorant composition of theinvention is within about ±10%, especially ±5% of the low-shearviscosity of the tint base from which the paint or other coating wasformed.

Another advantage of the invention is the colorant composition does nothave appreciable influence on the flow/leveling properties of a“greened” aqueous latex paint. In one embodiment, a paint of theinvention has a flow/level rating, measured at 25° C. according to ASTMStandard D4062-99, of at least 8 on a scale of from 1 to 10, with 10being the best flow/level characteristics. In another embodiment, apaint of the invention has a flow/level rating, measured in the sameway, of about 9. In another embodiment, a paint of the invention has aflow/level rating, measured in the same way, of about 10. On the onehand, if the rheology profile is flawed such that the paint is toostill, brush marks may be left when the paint is applied to a substrate.Conversely, if the rheology profile of an aqueous latex paint is suchthat the paint is too thin, the paint may be drippy when applied tosubstrate, such that the point film will run unacceptably. This is knownas “sag”, and the capacity of a paint to remain where applied ratherthan run or drip is called “sag resistance”. This property can bemeasured in different ways, but for purposes of the present invention isdetermined using a Leneta anti-sag matter. The higher the index numberis, the better the sag resistance is. Different sag resistance may bedictated by different applications. In general for architectural paints,an index number of 11 and above is considered to have excellent sagresistance. An index number from 8-10 has moderate or good sagresistance. An index number of 7 or below may cause significantdrippings or running of paints on the substrates during application.With our invention sag resistance is at least 8, preferably at least 10,and more preferably at least 11.

Further, the inventive paint's water sensitivity is not adverselyaffected. The term water sensitivity refers to the tendency of a paintto be degraded as a consequence of contact with water. This sensitivity,and conversely resistance to it, can be measured on draw downs dried fora controlled duration of time. A few drops of water can be deposited onthe paint surface for a suitable time period. The water is wiped off andthe wetted surface scratched with a finger nail to check the hardness ofthe film. The paint surface is rated from 1 to 5, with 5 designating thehardest film, and thus indicating the least amount of water sensitivity.In accordance with our invention, water sensitivity is at least 3,preferably at least 4, and more preferably at least 5.

Moreover, color transfer is similarly not unacceptably affected. Theterm “color transfer” refers to the incapability of a paint or othercoating to retain its constituent pigmentation under adverse conditions.Color transfer (or color rub-off), and conversely color transferresistance, for tinted aqueous latex paints or other water-bornecoatings can be measured utilizing draw downs dried for a controlledduration of time. More specifically, a typical color transfer test isperformed on drawdowns of paints or coatings to be tested, tined withcolorants or colorant compositions. The drawdowns are prepared usingBYK-Gardner byko-charts with a 3-mil bird applicator bar. The drawdownfilms are dried for 7 days at ambient conditions before testing. ABYK-Gardner Abrasion Tester with a boat weighing 1000 grams is used tomeasure color transfer. A wet white fabric sheet is attached to thelower surface of the boat which is placed on the drawdown films. Thefilms are scrubbed for 10 cycles and then the white fabric sheet isremoved from the boat and dried for one day. The dried white fabricsheet is examined for the color transferred from the drawdown films. Arating of 1 to 5 is assigned to each specimen with 5 being the mostresistant to color transfer. The invention yields color transfer of atleast 3, preferably at least 4, and more preferably 5.

The colorant composition of the invention is effective as an additive toa tint base, i.e., an aqueous latex base paint or other water-borne basedispersion, to tint (or color) same. A tint base typically compriseswater, at least one film-forming polymer and optionally one or moresurfactants dispersants. It will be understood by those of ordinaryskill in the art that the tint base can contain other additivesconventionally incorporated therein, including optionally (at least inthe case of tint bases) one or more white or other base pigments as wellas extender pigments, in customary amount. That said, the tint base hasa sufficiently low content of the target substances, i.e., VNCs, APEs ortheir derivatives, crystalline silica and formaldehyde, that therequirements of the invention can be met. The tint base is preferablysubstantially free, and more preferably substantially entirely free, ofthe target substances.

The colorant compositions may be added to tint bases at the point ofsale, prior to use or during the manufacturing process. The colorantcomposition embodiments of the invention are particularly beneficialbecause often industry claims concerning low VNC or othersolvent/additive/impurity levels relate to base paints or othercompositions. If colorant compositions combined with tint basesunfortunately have not been brought into environmental compliance, thenthe good work done in “cleaning up” the base material will be undonewhen the colorant composition is introduced, and this will carry overinto the final paint or other coating. By utilization of the colorantcompositions of the invention, the re-introduction of environmentallysignificant amount of VNCs, APEs and derivatives, crystalline silica,and formaldehyde is avoided. Extensive research and development has beenconducted to develop tint base products that meet various of thestandards mentioned above, particularly in respect of VNC levels. But,the standards and efforts to conform paint or other coatings theretotypically do not extend to colorant compositions. Novel colorantcompositions that can be formulated to meet the standards are describedherein. Thus, certain good embodiments of the inventive colorantcompositions are capable of being added to a tint base without:attenuation of Stormer low-shear viscosity stability; degradation of therheology profile, flow-leveling properties and sag; appreciablyheightened water-sensitivity; and exacerbated color transfer. Suchembodiments of the colorant composition comprise at least one pigment,water, and a color surfactant as aforesaid, with any VNCs being ofamount no greater than 1000 ppm, any APEs or derivatives thereof beingof amount no greater than 1000 ppm, any crystalline silica being ofamount no greater than 100 ppm, and any formaldehyde being of an amountno greater than 10 ppm.

Furthermore, in certain good embodiments blocking resistance and glossare likewise not adversely affected in any material sense as well.

The substantial elimination of solvent (non-aqueous), additive andimpurity content as described herein is achieved through recognition ofsuch elimination's feasibility (i.e., substantial elimination with highlevel performance-retention as aforesaid), and the implementation ofmaterials-selection and/or -processing measures to secure suitably purecomponents for making the inventive colorant composition and aqueouslatex paint or other water-borne coating. Accordingly, in certainpreferred embodiments none of the components of the colorantcomposition, or of the tint base with which it is combined, has a VNC-,APE- or APE-derivative, crystalline silica-, or formaldehyde-contentsuch that the combination of those components has an aggregate contentthereof greater than 0.30 weight %. Moreover, in certain goodembodiments neither any colorant composition nor tint base has a contentof any of those solvents and impurities which in the paint or coatingresulting from their combination is of amount greater than 0.15 weight%.

The requisite materials purity as described in the preceding paragraphis brought about by exercising careful attention to, including ifnecessary testing of, the levels of the aforementioned impurities andcontaminants in precursor substances utilized to formulate each colorantcomposition and tint base. In many instances this can be accomplished byresearching reliable published information about the constituents of theprecursor material materials typically obtained from outside sources(such as Materials Safety Data Sheets).

As mentioned previously, unlike the other target substances, crystallinesilica is normally present solely as an included impurity, and thus neednot be replaced by another material which conforms to the requirementsof our invention. As for the other target substances, removing them cansignificantly degrade performance. Thus, close attention must be paid totheir replacements. The following is a set of guidelines for selectionof suitable materials pursuant to our invention.

Low/zero-VNC materials include organic compounds with boiling pointsabove about 220° C., preferably above about 250° C. and more preferablyabove about 270° C., which therefore do not evaporate or flash, i.e.,which are non-volatile at normal indoor and outdoor temperatures. Somecoalescence aids can eventually form chemical bonds with polymers, andthus are capable of becoming a part of the polymer binder. Thesecoalescence aids work as plasticizers that soften the latex polymerparticles for film formation. Unlike traditional coalescence solventsthat evaporate from paints, coalescence aids with low/zero VNC's stay inthe dried paint films for an indefinite period of time.

Examples of suitable low- or zero-VNC coalescing agents that may be usedin the present invention in amounts that would not significantlyincrease the composition's VNC-content include (without limitation):dicarboxylic/tricarboxylic esters, such as trimethyl trimellitate(TMTM), tri-(2-ethylhexyl) trimellitate (TEHTM-MG),tri-(n-octyl,n-decyl) trimellitate (ATM), tri-(heptyl,nonyl)trimellitate (LTM) and n-octyl trimellitate (OTM); adipates, such asbis(2-ethylhexyl)adipate (DEHA), dimethyl adipate (DMAD), monomethyladipate (MMAD) and dioctyl adipate (DOA); sebacates, such as dibutylsebacate (DBS); maleates such as dibutyl maleate (DBM) and diisobutylmaleate (DIBM); benzoates; epoxidized vegetable oils such as M-ethyltoluene sulfonamide, N-(2-hydroxypropyl)benzene sulfonamide andN-(n-butyl)benzene sulfonamide; organophosphates such as tricresylphosphate (TCP) and tributyl phosphate (TBP); triethylene glycoldihexanoate; and tetraethylene glycol diheptanoate.

A useful coalescence aid is Optifilm Enhancer 300, which is a low-VOC,low odor “green” coalescent for emulsion paints. Sec “Optifilm Enhancer300, A Low Odor, Non-VOC, ‘Green’ Coalescent for Emulsion Paint,”Eastman Chemical Company, Publication M-AP315, April 2005. OptifilmEnhancer 300 can be utilized in formulating a variety of architecturalcoatings. With a boiling point of 281° C. and an empirical formula ofC₁₆H₃₀O₄, it is a non-volatile organic compound that is particularlysuitable for low odor flat and semi-gloss (including soft sheen, satin,vinyl silk and eggshell) interior wall paints. See “Eastman CoatingsFilm Technologies Film Optimization for Architectural Coatings,” EastmanChemical Company, 2005.

Another useful coalescence aid is Optifilm Enhancer 400, which is a verylow VOC, low odor coalescent that gives good film integrity, touch-upproperties and scrub resistance. With a boiling point of 344° C.,Optifilm Enhancer 400 is an alternate to ortho-phthalates such as butylbenzyl phthalate (BBP) and dibutyl phthalate (DBP) as plasticizers. See“Optifilm Enhancer 400—A Non-Phthalate Alternate,” Eastman ChemicalCompany, Publication TT-75, May 2006. Optifilm Enhancer 400 is able toreduce the minimum film forming temperature (MFFT) of various latexes ina more efficient manner than BBP. Because Optifilm Enhancer 400 becomesan integral part of the paint film, it adds to the flexibility of thepaint coating.

Yet another useful coalescence aid is Archer Reactive Coalescent (ArcherRC™), which is a propylene glycol monoester of unsaturated fatty acidsderived from vegetable oils. Archer RC™ is found to be nonvolatile whentested by EPA Method 24, possibly due to the oxidation and subsequentcrosslinking of its unsaturated component.

Still another useful coalescence aid is BASF Pluracoat™ CA 120 (ES8511).The Pluracoat™ brand materials are organic liquids based on proprietarytechnology from BASF. They are rated zero-VOC and can be used for low-or zero-VOC latex paints.

Coalescing agents in the nature of benzoate esters or alkyl benzoateesters, such as those sold under Benzoflex® and Velate®, and lowmolecular weight polyesters, such as those sold under Admex®, arelikewise useful.

All of these coalescents must be tested in the compositions andmonitored for performance and stability. In many cases, the formula orits components such as resins, dispersants or thickeners must bemodified to perform acceptably with low/zero VNC coalescents. Thesemodifications will be within the ordinary skill of the art, once theinvention's practitioner is in possession of the teachings herein.

Correspondingly, suitable surfactant and similar materials rated low- orzero-APE can be anionic and comprise C₁₃ alkyl ethoxylated to “low”extent (such as Rhodapex EST-30 SBL), and C₁₃ alkyl ethoxylated to“medium” extent (such as Rhodafac RS-610 and RS-710). These areavailable from Rhodia. Other Rhodia anionic materials containingproprietary hydrophobes ethoxylated to either “low” extent (such as Abex2005) or to “high” extent (such as Abex 18S and Abex 21355) are alsouseful.

Additionally, suitable surfactant and similar materials rated low- orzero-APE can be nonionic and comprise C₁₃ alkyl with an “HLB” range of14.0-15.0 (such as Rhodasurf 8C-720), or comprise C₁₆-C₁₈ alkyl with an“HLB” range of 17.5-19.0 (such as Rhodasurf CET55 E) or tristyrylphenol(such as Sopraphor TS80-60), with an “HLB” range of 17.5-19.0. These arelikewise available from Rhodia. Yet other Rhodia nonionic materialscontaining a proprietary hydrophobe are Abex 2525 with an “HLB” range of15.0-17.5 and Abex 2545 with an “HLB” range of 17.5-19.0.

As above, any modifications necessary in respect of other constituentswill be within the ordinary skill of the art once the invention'spractitioner is in possession of the disclosure herein.

Examples of pH adjustors with low/zero VNC's useful in practicing theinvention can include, but are not limited to, sodium hydroxide, sodiumcarbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate,potassium bicarbonate, and the like, and combinations of two or morethereof.

Suitable biocides that do not release or contain formaldehyde includethose sold under the names Kathon, Rocima, or Kordek from Rohm and Haas,or those containing 1,2-Benzisothiazolin-3-one (BIT) under the Proxelname, or zinc omadine available from Arch Biocides. or5-Chloro-2-Methyl-4-Isothiazolin-3-one (CIT) or2-Methyl-4-Isothiazolin-3-one (MIT) which are commercially availableunder the name Canguard from Dow Chemical Company. All of these biocidesexhibit a wide range of efficacy and need to be extensively screened andtested in the inventive formulations for performance and stability. Inmany eases blends or mixtures of these biocides may be needed. Apreferred biocide is Proxel BZ plus available from Arch Biocides, whichis a blend of two formaldehyde free compounds.

If there is any question about materials supplied by others, or if thematerials are made in-house, it is often prudent to verify by testing(at least on a random or representative basis) that appropriately lowlevels of impurities and contaminants are exhibited. The foregoingapplies also to colorant compositions and tint bases combined to formaqueous latex paints or other water-borne coatings, as well as to theproduct paints and coatings themselves. Once in possession of theteachings herein, one of ordinary skill in the art will be able toselect and carry out test procedures suitable for determining levels ofsolvents, additives and impurities as discussed, without the exercise ofinventive skill and as a matter of routine practice.

In the event any of the precursor materials, or a colorant compositionor tint base (or even a product paint or coating in principle) isbelieved to have too great a content of one or more of theaforementioned solvents and impurities, or this is indicated by theresults of testing, then suitable processing can be conducted to removeor decrease the content of impurity or contaminant as desired. Thenature of such processing will vary based on the impurity or contaminantin question. For example, VNCs and APEs as well as derivatives thereofcan be removed by any of the following measures, or combinations ofsame, its being understood that the techniques described can be appliednot only to latex materials but more broadly to a wide range ofdispersions.

Stripping is one of several methods that can be used to remove unwantedmaterials. Generally, stripping can be accomplished by means ofincreased temperature, decreased pressure or vacuuming, chemicalsolvents, steaming, various means of physical agitation, andcombinations thereof. Stripping can take place either in one continuousoperation or in batch or semi-batch operations. Various strippingprocesses are known in the art.

U.S. Pat. No. 3,003,930 discloses one stripping method. Morespecifically, the '930 patent discloses a tower of trays through which adispersion cascades in order that volatile organic hydrocarbons may beremoved. Increased temperature as well as steam or other inert gassesare used to volatize the volatile organic hydrocarbons. Measures aretaken to prevent foaming, which obstructs the escape of the hydrocarbonvapor, as well as re-entrainment of hydrocarbons.

U.S. Pat. No. 5,516,818, discloses a stripping process involvingcontacting a dispersion with a small amount of an organic solvent whichacts as a stripping aid and subjecting the dispersion to stripping usingsteam or an inert gas such as nitrogen. The solvent can be eitherintroduced in the stripping apparatus with the stripping gas, or it canbe mixed with the dispersion prior to introducing the latex into thestripping apparatus. The process of the '818 patent can be carried outin a batch or semi-batch mode.

U.S. Pat. No. 6,353,087 discloses a stripping process, wherein adispersion is heated and an inert gas such as steam is sparged throughthe dispersion to remove volatiles. This process also utilizes anagitator and a mechanical foam breaker. The '087 patent also teaches theuse of combinations of: (1) increasing the pH of the dispersion prior toand during stripping from 7 to 11; and (2) maintaining the temperatureof the dispersion at from 30° C. to 70° C. during stripping. In someembodiments, a vacuum is used so that stripping can be performed atlower temperatures.

U.S. Patent Application Publication No. 2006/0270815, entitledPolymerization of Diisopropenylbenzene, discloses the use of vacuumdistillation to remove residual compounds from dispersion, which may beused in paint.

In accordance with one particular aspect of the present invention, adispersion is treated by steam stripping at about 85° C. to 97° C. andapplying vacuum. Excessive foaming is controlled by the degree of vacuumapplied.

A distinct but related process called chemical chasing involves addingchemicals that react with unwanted materials. Such chemicals include,but are not limited to, tertiary butyl hydroperoxide, ammoniumpersulfate, potassium persulfate, or sodium persulfate which, forexample, may react with carbon-carbon double bonds of the unwantedmaterials. Chemical chasing can be used alone or with stripping tofurther reduce unwanted materials.

Yet another means of removing undesired material from polymerdispersions involves contacting the dispersion with a stripping medium,such as steam or gas, in the presence of an adsorbent material such ascarbon black, activated charcoal, silica gel, aluminum oxide or ferricoxide. For instance, in U.S. Pat. No. 6,348,636, discrete quantities ofthe particulate adsorbent material are provided in permeableflow-through enclosures (e.g., in a manner analogous to teabags).Preferred adsorbent materials of the '636 patent include activatedcarbon, e.g., Cal 12×40, a granular decolorizing carbon sold by CalgonCarbon Corporation.

Columns or ion exchange columns may also be used to purify a dispersion.For example, U.S. Pat. No. 4,130,527 discloses that an unwantedmaterial, such as vinyl chloride monomer, can be removed from an aqueousdispersion, such as polyvinyl chloride, by allowing the dispersion toflow as a thin liquid film down the inner surface of a substantiallyvertical column at sub-atmospheric pressure countercurrent to anascending flow of steam. In Example 1 of U.S. Pat. No. 5,055,197, an ionexchange column is used to remove an unwanted material. Another exampleof the use of a column apparatus to purify polymer dispersions isdisclosed in U.S. Pat. No. 6,740,691. In the '691 patent, alatex/dispersion is cascaded down a column equipped with internals incounter-current flow with water vapor and/or air. Internals such asrandom packing, structured packing and especially trays are disposedthrough the column to provide multiple stages of mass transfer.

For its part, crystalline silica can be removed by precipitation, suchas in precipitated calcium carbonates, or by washing.

Other processing measures which yield the result sought can also beutilized as long as they are not antithetical to attainment of theobjects of the invention. It goes almost without saying, especially whentwo or more solvents, additives or impurities are being treated, thatthe various processing steps can be utilized separately, sequentially,simultaneously or in any other practical manner.

The definitions hereinafter will be useful in understanding the scope ofthe invention and are applicable to the entire discussion in thisspecification.

As used in this specification, “alkyl” shall be deemed to encompassspecies comprising one or more of a saturated straight chain or branchednoncyclic hydrocarbon having from 1 to 30 carbon atoms. Representativesaturated straight chain alkyls include -methyl, -ethyl, -n-propyl,-n-butyl, -n-pentyl, -n-hexyl, -n-heptyl, -n-octyl, -n-nonyl, -n-decyland the like. Representative saturated branched alkyls include-isopropyl, -sec-butyl, -isobutyl, -tert-butyl, -isopentyl,-2-methylbutyl, -3-methylbutyl, -2,2-dimethylbutyl, -2,3-dimethylbutyl,-2-methylpentyl, -3-methylpentyl, -4-methylpentyl, -2-methylhexyl,-3-methylhexyl, -4-methylhexyl, -5-methylhexyl, -2,3-dimethylbutyl.-2,3-dimethylpentyl. -2,4-dimethylpentyl, -2,3-dimethyleyl,-2,4-dimethylhexyl, -2,5-dimethyleyl, -2,2-dimethylpentyl,-2,2-dimethylhexyl, -3,3-dimethylpentyl, -3,3-dimethylhexyl,-4,4-dimethylhexyl, -2-ethylpentyl, -3-ethylpentyl, -2-ethylhexyl,-3-ethylhexyl, -4-ethylhexyl, -2-methyl 2-ethylpentyl,-2-methyl-3-ethylpentyl, -2-methyl-4-ethylpentyl, -2-methyl2-ethylhexyl, -2-methyl-3-ethylhexyl, -2-methyl-4-ethylhexyl,-2,2-diethylpentyl, -3,3-dethylhexyl, -2,2-dethylhexyl, -3,3-dethylhexyland the like.

Also as used in this specification, “alkylphenyl” shall be deemed toencompass species comprising one or more phenyl groups each substitutedwith at least one alkyl group, where alkyl is as defined above.

Further, as used in this specification, “styrylphenyl” shall be deemedto encompass species comprising a phenyl group substituted with a styrylgroup, i.e., a vinyl benzene group where the unsubstituted carbon atomof the vinyl is bonded to the phenyl ring. Thus, in the strictest sense,in a monostyrylphenyl group, one vinyl benzene group is bonded tophenyl; in a distyrylphenyl group, two vinyl benzene groups are bondedto phenyl; and in a tristyrylphenyl group, three vinyl benzene groupsare bonded to phenyl. However, it is to be understood that as, e.g., acommercially-available tristyrylphenylpoly(ethyleneoxy) (meth)acrylate(i.e., the compound designated by CAS Reg. Number 174200-85-2) can be amixture of monostyrylphenylpoly(ethyleneoxy) (meth)acrylate,distyrylphenylpoly(ethyleneoxy) (meth)acrylate and/ortristyrylphenylpoly(ethyleneoxy) (meth)acrylate, as used herein, theterm “tristyrylphenyl,” when used either alone or as a portion of achemical name and unless otherwise indicated, includes monostyrylphenyl,distyrylphenyl, tristyrylphenyl, or a mixture thereof.

Colorant Compositions

The inventive colorant compositions typically comprise not only water, apigment and a copolymer surfactant (which can be present as a dispersionof the polymer), but can also contain: one or more additionalsurfactants and/or dispersants; one or more water-dispersible polymers;one or more low number average molecular weight polymers (such aspolyethylene glycol or polypropylene glycol) each with an averagemolecular weight of about 300-about 8,000 Daltons; and one or morerheology modifiers, for instance thickeners, especially associativethickeners; provided however that none of such further components shallconstitute, incorporate or be accompanied by a VNC, an APE or derivativethereof, crystalline silica, or formaldehyde. In some cases the colorantcomposition can even comprise a film-forming or other latex bindercomponent, though the colorant composition embodiments do not containfilm-forming latex binder amounts sufficient for the formation of asuitable paint film, and thus do not constitute a tint-base or otheraqueous polymer dispersion, or a latex paint or other water-bornecoating as meant in this disclosure.

Each colored pigment included in a colorant composition (or an aqueouslatex paint or water-borne coating, for that matter) of the inventioncan be an organic pigment or an inorganic pigment; such pigments arewell-known in the art. Organic pigments include phthalocyanine blue,phthalocyanine green, monoarylide yellow, diarylide yellow,benzimidazolone yellow, heterocyclic yellow, DAN orange, quinacridonemagenta, quinacridone violet, organic reds, including metallized azoreds and nonmetallized azo reds, and the like. Exemplary azo redsinclude lithols, lithol rubine, toluidine red, naphthol red andquinacridone red. Metallized azo reds are salts containing metalcations, such as barium or calcium salts of azo reds, e.g., calciumlithol rubine and barium lithol red. Nonmetallized azo reds aresubstantially free of metal cations. Inorganic pigments include titaniumdioxide white, carbon black, lampblack, black iron oxide, yellow ironoxide, brown iron oxide, red iron oxide, and the like.

Each white pigment, off-white pigment or extender pigment included in acolorant composition or (aqueous latex paint or water-based coating) ofthe invention can comprise a titanium dioxide, or other suitable whitepigment, off-white pigment or extender pigment, for example talc orsilica, known in the art.

The copolymer surfactant comprises one or more component unitscorresponding to unsaturated carboxylic acid and/or unsaturatedanhydride monomers. Typically, a copolymer surfactant has a polymericbackbone chain (“chain”) comprising at least one hydrophobe, in anotherembodiment two or more or hydrophobes, and a plurality of hydrophiles,such as two or more monomer units of an α,β-ethylenically unsaturatedcarboxylic acid or anhydride, copolymerized into the copolymer backboneof the copolymer surfactant. The surfactant monomer contributes towardshydrophobicity, e.g., by its alkyl, or tristyrylphenyl groups, therebyfacilitating the desired association with various types of hydrophobicgroups of pigments and of other coating ingredients. Hydrophilic groups,such as carboxylic acid and/or anhydride groups, impart solubility tothe copolymer surfactant in an aqueous phase, when neutralized, and alsofacilitate the dispersion of inorganic pigments. Other comonomercomponents of the copolymer surfactant can be used to adjust the balancebetween the hydrophobicity and hydrophilicity of the copolymersurfactants.

Representative species include mono and dicarboxylic acids, such asacrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleicacid, fumaric acid, angelic acid, glutaconic acid, cinnamic acid,carboxyl cinnamic acid, styrene dicarboxylic acid, and the like.Half-esters of the dicarboxylic acids with alkanols can also be used, ascan anhydrides. Maleic anhydride, 4-vinyl-isobenzofuran-1,3-dione and5-vinyl-isobenzofuran-1,3-dione are exemplary C₃-C₁₂ α,β-ethylenicallyunsaturated carboxylic anhydrides.

In various good embodiments of the invention a copolymer chain includesunits derived from one and only one C₃-C₁₂ α,β-ethylenically unsaturatedcarboxylic acid or anhydride monomer. In other embodiments a copolymerchain includes units derived respectively from two separate C₃-C₁₂α,β-ethylenically unsaturated carboxylic acid or anhydride monomerswhich are present in a copolymer surfactant chain. And in yet otherembodiments a copolymer chain includes units derived respectively fromthree C₃-C₁₂ α,β-ethylenically unsaturated carboxylic acid or anhydridemonomers. It is, of course, to be understood that when unitscorresponding respectively to two or more separate C₃-C₁₂α,β-ethylenically unsaturated carboxylic acid or anhydride monomers arepresent in a copolymer chain, each separate monomer can be an acid or ananhydride independently of the other(s).

In certain good embodiments, the one or more unsaturated carboxylic acidor anhydride monomers are present in the polymerization process at aconcentration of from about 10% to about 80% by weight, preferably about15% to about 50% by weight, and more preferably about 20% to about 45%by weight, based on the total weight of all monomers and chain transferagent(s) from which the copolymer is formed. In another embodimentcomponent units corresponding to acrylic acid are present at aconcentration of from about 20% to about 45% by weight, based on thetotal weight of all monomers and chain transfer agent(s) from which thecopolymer is formed.

The copolymer surfactant also comprises vinyl monomers. Monomers of thistype suitable for use in accordance with the present invention includeany compounds having vinyl functionality, i.e., ethylenic unsaturation,exclusive of compounds having acrylic functionality, e.g., acrylic acid,methacrylic acid, esters of such acids, acrylonitrile and acrylamides.Preferably, the vinyl monomers are selected from the group consisting ofvinyl esters, vinyl aromatic hydrocarbons, vinyl aliphatic hydrocarbons,vinyl alkyl ethers and mixtures thereof.

Suitable vinyl monomers include vinyl esters, such as, for example,vinyl propionate, vinyl laurate, vinyl pivalate, vinyl nonanoate, vinyldecanoate, vinyl neodecanoate, vinyl butyrates, vinyl benzoates, vinylisopropyl acetates and similar vinyl esters; vinyl aromatichydrocarbons, such as, for example, styrene, methyl styrenes and similarlower alkyl styrenes, chlorostyrene, vinyl toluene, vinyl naphthaleneand divinyl benzene; vinyl aliphatic hydrocarbon monomers, such as, forexample, vinyl chloride and vinylidene chloride as well as alpha olefinssuch as, for example, ethylene, propylene, isobutylene, as well asconjugated dienes such as 1,3-butadiene, methyl-2-butadiene,1,3-piperylene, 2,3-dimethyl butadiene, isoprene, cyclohexene,cyclopentadiene, and dicyclopentadiene; and vinyl alkyl ethers, such as,for example, methyl vinyl ether, isopropyl vinyl ether, n-butyl vinylether, and isobutyl vinyl ether.

Examples of vinyl compounds typically comprising an α,β-ethylenicallyunsaturated vinyl monomer which contains from 2 to 12 carbon atomsinclude esters of acrylic and methacrylic acid, such as methylmethacrylate, ethyl acrylate, ethyl methacrylate, 2-ethylhexyl acrylate,butyl acrylate, butyl methacrylate, 2-hydroxyethyl acrylate,2-hydroxybutyl methacrylate and the like; vinyl esters, such as vinylacetate, vinyl butyrate, vinyl caprolate and the like; nitrile monomers,such acrylonitrile, methacrylonitrile and the like; vinyl chloride;vinylidene chloride; and the like. In another embodiment, the C₃-C₁₂α,β-ethylenically unsaturated vinyl monomer is butyl acrylate, ethylacrylate, ethyl methacrylate, methyl methacrylate, vinyl acetate,acrylonitrile, or a mixture thereof. In another embodiment, the C₃-C₁₂α,β-ethylenically unsaturated vinyl monomer is butyl acrylate, ethylmethacrylate, methyl methacrylate, vinyl acetate, or a mixture thereof.In another embodiment, the C₃-C₁₂ α,β-ethylenically unsaturated vinylmonomer is butyl acrylate, ethyl methacrylate, vinyl acetate, or amixture thereof.

While theoretically styrene could be characterized as a vinyl, forpurposes of this disclosure suitable moieties which contain a styrenicgroup are characterized separately from other vinyl species. That beingsaid, component units corresponding to styrenic monomers are likewisesuitable. They include styrenic monomers, such as styrene, vinyltoluene,t-butylstyrene, isopropylstyrene, p-chlorostyrene and the like.

The copolymer surfactant can also comprise acrylic monomers. Suchmonomers suitable for use in accordance with the present inventioncomprise any compounds having acrylic functionality. Preferred acrylicmonomers are selected from the group consisting of alkyl acrylates,alkyl methacrylates, acrylate acids and methacrylate acids as well asaromatic derivatives of acrylic and methacrylic acid, acrylamides andacrylonitrile. Typically, the alkyl acrylate and methacrylic monomers(also referred to herein as “alkyl esters of acrylic or methacrylicacid”) will have an alkyl ester portion containing from 1 to about 18,preferably about 1 to 8, carbon atoms per molecule.

Suitable acrylic monomers include, for example, methyl acrylate andmethacrylate, ethyl acrylate and methacrylate, butyl acrylate andmethacrylate, propyl acrylate and methacrylate, 2-ethyl hexyl acrylateand methacrylate, cyclohexyl acrylate and methacrylate, decyl acrylateand methacrylate, isodecyl acrylate and methacrylate, benzyl acrylateand methacrylate, isobornyl acrylate and methacrylate, neopentylacrylate and methacrylate, 1-adamantyl methacrylate and various reactionproducts such as butyl, phenyl, and cresyl glycidyl ethers reacted withacrylic and methacrylic acids, hydroxyl alkyl acrylates andmethacrylates such as hydroxyethyl and hydroxypropyl acrylates andmethacrylates, amino acrylates, methacrylates as well as acrylic acidssuch as acrylic and methacrylic acid, ethacrylic acid,alpha-chloroacrylic acid, alpha-cyanoacrylic acid, crotonic acid,beta-acryloxy propionic acid, and beta-styryl acrylic acid.

Further examples of suitable monomers from which are derived componentunits of the copolymer surfactants include:

-   -   vinyl acetate, vinyl propionate, vinyl butyrate, vinyl        isobutyrate, vinyl benzoate, vinyl m-chlorobenzoate, vinyl        p-methoxybenzoate, vinyl alpha-chloroacetate, vinyl toluene,        vinyl chloride, para vinyl benzyl alcohol, etc.    -   styrene, alpha-methyl styrene, alpha-ethyl styrene, alpha-bromo        styrene, 2,6-dichlorostyrene, etc.;    -   allyl chloride, allyl acetate, allyl benzoate, ally        methacrylate, etc.;    -   ethylene, acrylonitrile, methacrylonitrile, dimethyl maleate,        isopropenyl acetate, isopropenyl isobutyrate, acrylamide,        methacrylamide, 1,3-butadiene, etc.;    -   acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate,        propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl        acrylate, ethylhexyl acrylate, amyl acrylate,        3,5,5-trimethylhexyl acrylate, methyl methacrylate, ethyl        methacrylate, propyl methacrylate, dimethylaminoethyl        methacrylate, isobornyl methacrylate, t-butyl methacrylate,        ethyl tiglate, methyl crotonate, ethyl crotonate, 2-hydroxyethyl        acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,        4-hydroxybutyl methacrylate, 2-hydroxypropyl methacrylate,        3-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 4        hydroxypypentyl acrylate, 2-hydroxyethyl ethacrylate,        3-hydroxybutyl methacrylate, 2-hydroxyethyl chloroacrylate,        diethyleneglycol methacrylate, tetra ethylene glycol acrylate,        etc.

The copolymer surfactant also comprises one or more component unitscorresponding to a surfactant monomer. As used herein, the expression“surfactant monomer” shall be deemed to mean a compound having ahydrophilic moiety containing an unsaturated bond capable of enteringinto a polymerization reaction, and a hydrophobic moiety, connected by abridging moiety comprising—and preferably joined to one another by abridging moiety consisting essentially of—a polymeric moiety withrepeating carbonyl groups. The expression encompasses, but is notlimited to, species comprising one or more of at least one acrylic esteror methacrylic ester, i.e., a “(meth)acrylic ester,” of an ethoxylatedhydrophobic moiety, for instance, alkyl, alkylphenyl, monostyrylphenyl,distyrylphenyl, tristyrylphenyl and the like. The surfactant monomer canhave a structure as depicted by the formula:

H₂C═C(X)—C(O)O-E-R  (1)

where X is hydrogen or methyl, E is a hydrophilic moiety such asethoxylate and the like, and R is a hydrophobic moiety such as alkyl,alkylphenyl, monostyrylphenyl, distyrylphenyl or tristyrylphenyl and thelike. Representative suitable surfactant monomers include the acrylic ormethacrylic acid esters of nonionic surfactant alcohols, such asalkylpolyethyleneoxy (meth)acrylates or alkylphenylpolyethyleneoxy(meth)acrylates, where the alkyl group contains, independently, from 1to 30 carbon atoms, and the tristyrylphenylpoly(ethyleneoxy)(meth)acrylates. In other embodiments, however, multiple surfactantmonomers are present in a copolymer surfactant chain and provide aplurality or combination of the alkyl, or tristyrylphenyl hydrophobicgroups. It is to be understood that, as used herein, the term“tristyrylphenyl,” either alone or as a portion of a chemical name andunless otherwise indicated, includes any and all of monostyrylphenyl,distyrylphenyl, tristyrylphenyl, and mixtures of two or more thereof.The alkylpolyethyleneoxy (meth)acrylate or alkylphenylpolyethyleneoxy(meth)acrylate may have an alkyl group which contains, independently,from 1 to 22 carbon atoms or the alkylpolyethyleneoxy (meth)acrylate oralkylphenylpolyethyleneoxy (meth)acrylate may have an alkyl group whichcontains, independently, from 9 to 22 carbon atoms.

Additional examples of surfactant monomers include one or more of anonylpoly(ethyleneoxy) acrylate, decylpoly(ethyleneoxy) acrylate,undecylpoly(ethyleneoxy) acrylate, oleylpoly(ethyleneoxy)methacrylate,behenylpoly(ethyleneoxy)methacrylate,tristyrylphenylpoly(ethyleneoxy)methacrylate, or a mixture thereof.Still further examples of surfactant monomers encompass speciescomprising one or more of behenylpoly(ethyleneoxy) acrylate,behenylpoly(ethyleneoxy)methacrylate, decylpoly(ethyleneoxy) acrylate,decylpoly(ethyleneoxy)methacrylate, tristyrylphenylpoly(ethyleneoxy)acrylate, tristyrylphenylpoly(ethyleneoxy)methacrylate, or a mixturethereof as well as species comprising one or more ofbehenylpoly(ethyleneoxy)methacrylate, decylpoly(ethyleneoxy) acrylate,tristyrylphenylpoly(ethyleneoxy) acrylate,tristyrylphenylpoly(ethyleneoxy)methacrylate, or a mixture thereof.

Further examples of surfactant monomers are species comprising one ormore of a tristyrylphenylpoly(ethyleneoxy) acrylate,tristyrylphenylpoly(ethyleneoxy)methacrylate,tristyrylphenylpoly(ethyleneoxy) acrylate andtristyrylphenylpoly(ethyleneoxy)methacrylate, or a mixture thereof.Also, the surfactant monomer known as Nopol (described in U.S. Pub. App.No. US20060270563, incorporated by reference herein) may be used.

The copolymer surfactant can be a mono-hydrophobe, i.e., it can containa single hydrophobic group per polymer chain. In another embodiment, thecopolymer surfactant can contain multiple (i.e., two or more)hydrophobes, each of which can be the same or different, per polymerchain. In other embodiments, the copolymer surfactant can be adi-hydrophobe and contain two hydrophobe groups, which can be the sameor different, per polymer chain. Conventional hydrophobically modifiedalkali soluble/swellable copolymers (i.e., HASCs) disclosed above arethese types of surfactants. Other hydrophobically modifiedsoluble/swellable copolymers are known.

It will be understood by one of ordinary skill in the art that componentunits corresponding to one or more types of surfactant monomers can bepresent. In some embodiments, one surfactant monomer unit is present ina copolymer surfactant chain. Thus, in various embodiments, twosurfactant monomer units, which can, of course, be the same ordifferent, are present in a copolymer surfactant chain. In yet otherembodiments, three surfactant monomer units, which can, of course, bethe same or different, are present in a copolymer surfactant chain. Instill another embodiment, an average of one surfactant monomer unit ispresent in a copolymer surfactant chain. In another embodiment, anaverage of from about one to about two surfactant monomer units arepresent in a copolymer surfactant chain. In a further embodiment, anaverage of at least about two surfactant monomer units are present in acopolymer surfactant chain. The amount of one or more surfactantmonomers is preferably from about 0.01% to about 20% by weight, morepreferably be from about 0.03% to about 16% by weight, and especiallypreferably about 0.5% to about 13% by weight, based on the total weightof all monomers and chain transfer agent(s) from which the copolymer isformed.

In each of the surfactant monomers containing (ethyleneoxy) groups, thenumber of ethylene oxide units present is preferably from about 4 toabout 200, more preferably from about 4 to about 60, and especiallypreferably from about 10 to about 40.

Once in possession of the teachings herein, one of ordinary skill willbe able to determine, as a matter of routine testing and without undueexperimentation, amounts of copolymer surfactant suitably incorporatedin colorant compositions to secure the desired surfactant effect. Theinformation, in the Examples hereinafter, confirms same. In various goodembodiments of the invention, the amount of copolymer surfactantincorporated in the colorant composition is from 0.5 to 16, preferablyfrom 1 to 12, and more preferably from 2 to 8, weight percent based onthe total amount of solids in the colorant composition.

In certain good embodiments, the one or more acrylic monomers, vinylmonomers and/or styrenic monomers are present in the polymerizationprocess at a concentration of from about 10% to about 90% by weight,preferably from about 10% to about 60% by weight, based on the totalweight of all monomers and chain transfer agent(s) from which thecopolymer is formed.

In one embodiment, where the surfactant monomer is selected fromnonylpoly (ethyleneoxy) acrylate, decylpoly (ethyleneoxy) acrylate,undecylpoly (ethyleneoxy) acrylate, oleylpoly (ethyleneoxy)methacrylate,behenylpoly (ethyleneoxy)methacrylate, tristyrylphenylpoly(ethyleneoxy)methacrylate, or a mixture thereof, copolymer is formedfrom an amount of surfactant monomer(s) is from about 0.5% to about 13%by weight, based on the total weight of all monomers and chain transferagent(s) from which the copolymer is formed.

The colorant composition can further comprise at least one associativethickener.

The colorant composition can also comprise low molecular weight polymerglycols. Suitable ones include polyethylene glycol, polypropylene glycoland the like with a number average molecular weight of about 300-about8,000 Daltons. These substances can affect the drying properties ofcolorant compositions of the invention. At least one of these lowmolecular weight polymer glycols can be present in colorant compositionsof the invention, but their use is optional.

The copolymer surfactants of the invention can also be used incombination with other water-soluble polymers, including but not limitedto polycarboxylic acids, copolymers comprising monomers containing acarboxylic acid, water soluble copolymers, cellulose derivatives, saltsof polyacrylic acids, salts of copolymers comprising monomers containingan acrylic acid, polyvinylpyrrolidone, and copolymers comprisingvinylpyrrolidone monomer. In another embodiment, the water-solublepolymer is a salt of a polyacrylic acid, a salt of a copolymercomprising a monomer containing an acrylic acid, or a mixture thereof.Conventional emulsifiers or surfactants, i.e., anionic, cationic,nonionic, amphoteric surfactants and mixtures thereof, can also be usedwith the copolymer surfactants of the invention.

Exemplary associative thickeners include nonionic hydrophobicallymodified ethylene oxide urethane block copolymers,hydrophobically-modified polyethers, hydrophobically-modified alkalisoluble emulsions, hydrophobically-modified poly(meth)acrylic acid,hydrophobically-modified hydroxyethyl cellulose,hydrophobically-modified poly(acrylamide), and mixtures thereof.

In certain good embodiments of the invention the copolymer surfactantconsists essentially of

(a) from about 10% to about 80% by weight of methacrylic or acrylicacid,

(b) from about 10% to about 80% by weight of a first vinyl ester whichis alkyl methacrylate, the alkyl of which is of from 2 to 12 carbonatoms, and a second vinyl ester of from 2 to 12 carbon atoms, and

(c) from about 0.01% to about 20% by weight of at least one surfactantmonomer, wherein each the surfactant monomer is either an acrylic ormethacrylic ester moiety joined with a hydrophobic moiety which istristyrylphenyl by a bridging group consisting essentially of apoly(ethyleneoxy).

In further embodiment, the copolymer surfactant may comprise thefollowing monomers:

(a) from about 10% to about 80% by weight of methacrylic or acrylicacid,

(b) from about 10% to about 80% by weight of ethyl methacrylate andvinyl acetate, and

(c) from about 0.01% to about 20% by weight tristyrylphenylpoly(ethyleneoxy)methacrylate.

As such, the surfactant monomer may be an acrylic or methacrylic estermoiety joined with a hydrophobic moiety selected from the groupconsisting of monostyrylphenyl, distyrylphenyl and tristyrylphenyl by abridging group consisting essentially of a poly(ethyleneoxy) moiety. Forexample, the poly ethyleneoxy) moiety has from about 4 to about 200ethyleneoxy units.

The copolymer surfactants can be prepared by solution copolymerizationof the monomers through free-radical, stable free-radical (e.g., usingthe well-known compound TEMPO), anionic or cationic polymerization in asolvent, such as an oxygenated solvent, or in a mixture of solvents.Glycols are exemplary oxygenated solvents. Exemplary glycols includeethylene glycol, propylene glycol, glycerol, diethylene glycol,triethylene glycol, tetraethylene glycol, and other polyethylene glycolsof relatively low number average molecular weight, e.g., about 300-about8,000 Daltons. Cellosolves and cellosolve derivatives, such ascellosolve acetate, can also be used as the oxygenated solvent.

In another embodiment, the copolymer surfactants are prepared byemulsion copolymerization of the monomers in a continuous aqueous phaseemulsion using an emulsifier. This can be done by conventional emulsionpolymerization at a pH below about 5.0 using a conventional free-radicalproducing initiator(s), such as ammonium persulfate, sodium persulfate,potassium persulfate, cumene hydroperoxide, tert-butyl hydroperoxide,benzoyl peroxide, acetyl peroxide, lauroyl peroxide, peracetic acid,perbenzoic acid and/or 2,2′-azobisisobutyronitrile. The amount ofinitiator used can be from about 0.05% to about 3.5% by weight based ontotal weight of all monomers present, preferably about 0.75% to about3.2% by weight based on total weight of all monomers present.Polymerization is often carried out under a relatively inert atmosphere,such as is provided by nitrogen or argon gas, at a temperature of fromabout 60° C. to about 90° C. Of course, as known to one skilled in theart, greater or lesser amounts of initiator and higher or lowertemperatures can be used depending on the circumstances. Thepolymerization can be carried out in a batch-wise or step-wise manner orwith continuous addition of monomers in a conventional manner. Thesurfactant monomers can be fed simultaneously with other monomers, or befed after a proportion of other monomers has been reacted.

Customarily, at least one anionic, cationic, nonionic or amphotericemulsifier is used in the emulsion copolymerization in which thecopolymer surfactant is prepared. When more than one emulsifier ispresent, each additional emulsifier may be designated a co-emulsifier. Awide variety of emulsifiers are available, for example, many are listedin McCutcheon's Emulsifiers & Detergents, North American Ed.,Manufacturing Confectioner Pub. Co., Glen Rock. N.J., 1988, pp. 1-217.The emulsifier can be nonionic, have an anionic charge, have a cationiccharge, or have both an anionic and a cationic charge, e.g., anamphoteric emulsifier, where each charge has associated with it asuitable counter ion; numerous examples of each are known in the art.See Lynn, Jr. et al., “Surfactants” in Kirk-Othmer Encyc. of Chem.Technol., 4th Ed., John Wiley & Sons, New York, 1997, Vol. 23. pp.483-541.

Commonly utilized nonionic emulsifiers are alkylphenol ethoxylates andderivatives thereof, such as nonylphenol ethoxylate. Of course,copolymer surfactants made using such emulsifiers need to be “cleared”as not containing unduly large amounts of APEs or derivatives of same asa result of their production process.

Anionic emulsifiers include but are not limited to alkali metal alkylaryl sulfonates, alkali metal alkyl sulfates, the sulfonated alkylesters, e.g., sodium dodecylbenzene sulfonate, sodiumdisecondary-butylnaphthalene sulfonate, sodium lauryl sulfate, disodiumdodecyldiphenyl ether disulfonate, disodium n-octadecylsulfosuccinamate,sodium dioctylsulfosuccinate, and the like. Cationic emulsifiers includebut are not limited to amines, e.g., aliphatic mono-, di- and polyaminesderived from fatty and rosin acids; and quaternary ammonium salts, e.g.,dialkyldimethyl and alkyltrimethyl ammonium salts, alkylbenzyldimethylammonium chlorides, and alkylpyridinium halides.

Amphoteric emulsifiers include but are not limited to imidazolinederivatives, such as disodium lauroampho diacetate, disodium cocoamphodiacetate, sodium cocoampho acetate, sodium cocoampho propionate, sodiumlauroampho acetate, disodium cocoampho dipropionate, cocoamphodipropionic acid, sodium capryloampho carboxylate, sodium cocoamphohydroxypropyl sulfonate, sodium capryloampho hydroxypropyl sulfonate,and the like; alkyl betaines, such as lauramidopropyl betaines, cocodimethyl betaine, oleamidopropyl betaine, and the like; sultaines, suchas alkylether hydroxypropyl sultaine, cocamidopropyl hydroxyl sultaine,and the like; dihydroxyethyl glycinates, such as dihydroxyethyl tallowglycinate and the like; and aminopropionates, such as sodium lauriminodipropionate and the like. The foregoing emulsifiers can be separatelyor as a mixture of two or more thereof.

When a copolymer surfactant is prepared by emulsion polymerization, theamount of emulsifier used can be from about 0.2% to about 10% by weightbased on the total weight of the emulsion, preferably from about 0.5% toabout 10% by weight based on the total weight of the emulsion, morepreferably from about 0.5% to about 4.0% by weight based on the totalweight of the emulsion.

A copolymer surfactant typically has a number average molecular weightof from about 400 Daltons to about 500,000 Daltons, preferably fromabout 400 to about 200.000 Daltons, more preferably from about 1,200 toabout 200,000 Daltons.

One interesting type of copolymer surfactant comprises component unitsderived from one or more members of the group consisting of acrylicmonomers, vinyl monomers and styrenic monomers; component units derivedfrom one or more members of the group consisting of carboxylic acidmonomers and anhydride monomers, each of which has an unsaturated bondcapable of entering into a polymerization reaction; one or morecomponent units corresponding to a surfactant monomer; component unitscorresponding to one or more chain transfer agents; and component unitscorresponding to one or more crosslinking monomers, each of whichcrosslinking monomers has at least three unsaturated bonds capable ofentering into a polymerization reaction, is provided.

These copolymer surfactants typically have a multi-branched structurewith a degree of branching which is the result of the presence in thecopolymer of component units corresponding to a crosslinking monomerhaving at least three unsaturated bonds capable of entering into apolymerization reaction, and the interplay between such units and thechain transfer agent(s) which reacts with propagating branches so as toterminate their growth with the result that new branches form atdifferent sizes provided by the component corresponding to thecrosslinking monomer.

Correlatively, the expression “hyperbranched copolymer” means acopolymer with one or more constituent component unit(s) correspondingto a crosslinking monomer having at least three unsaturated bondscapable of entering into a polymerization reaction.

One or more chain transfer agents are used to effect “hyperbranching” ofthe copolymers of the invention. Chain transfer agents useful inpreparing hyperbranched copolymers of the invention include linear orbranched C₄-C₂₂ alkyl mercaptans (such as n-dodecyl mercaptan andt-dodecyl mercaptan), isopropanol, halogenated compounds, n-butylmercaptan, n-amyl mercaptan, i-octyl 2-mercaptoproprionate, alkylthioglycolate, mercaptoproprionic acid and alkyl mercaptoalkanoate. Morespecifically, when incorporated into a growing branch of the copolymer,chain transfer agents terminate extension of that branch. As discussedlater, the use of crosslinking monomer(s) results in hyperbranchingwhere many branches form and grow in length. These branches propagate atthe numerous branch points available. This gives rise to an unusuallylarge number of branches. In order to regulate the molecular weight ofthe hyperbranched copolymer, a chain transfer agent, or combination ofmultiple agents is utilized to react with the component unit at the endof the branch, to terminate growth of the branches before they increasein size to the length which would otherwise be attained in theirabsence, thereby providing a ceiling on the molecular weight. Thus, themolecular weight of the hyperbranched copolymer can be regulated byaltering the amount of chain transfer agent used in embodiments of thepresent invention.

In various good embodiments, one or more a chain transfer agents arepresent in an amount of about 0.02% to about 8% by weight, and morepreferably in an amount of about 1% to about 3% by weight, of the totalamount of monomers and chain transfer agent(s) from which thehyperbranched copolymer is formed.

Furthermore, the copolymer of the invention also comprises copolymerunits corresponding respectively to one or more crosslinking monomers.Incorporation of these units has the effect of contributing tomodification of the molecular weight of and promoting enhanced thebranching of the copolymers of the invention.

Crosslinking monomers suitable for practice of the invention havemultiple, and in any event at least two reactive unsaturated, preferablyethylenically unsaturated, bonds in a single molecule. In certain goodembodiments of the invention, the crosslinking monomer(s) used has atleast three reactive ethylenically unsaturated bonds in a singlemolecule. Such compounds are referred to as “multifunctionalcrosslinking monomers.” Component units corresponding to one or moremultifunctional crosslinking monomers are, for example, unitscorresponding to one and only one multifunctional crosslinking monomer,or alternatively, units corresponding to one or another of multipledifferent multifunctional crosslinking monomers that all are used in thepolymerization reaction, to yield the increased amount of branchingsought.

Examples of the foregoing are component units corresponding tomulti-functional crosslinking monomers such as trimethylolpropanetriacrylate, ethoxylated trimethlolpropane triacrylate, propoxylatedtrimethylolpropane triacrylate, propoxylated glyceryl triacrylate,pentaerythritol triacrylate, tris (2-hydroxy ethyl) isocyanuratetriacrylate, ditrimethylolpropane tetraacrylate, pentaerythritoltetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaacrylateester and dipentaerythritol pentaacrylate.

Frequently, unsaturated crosslinking monomer is present in an amountfrom about 0.5% to about 70%, preferably from about 0.5% to about 10%,more preferably from about 0.5% to about 5% by weight, of the monomersand chain transfer agent(s) from which the copolymer is formed (thoughthose of ordinary skill, equipped with the teachings herein, will beable to determine, as a matter of routine experimentation, instances inwhich greater or lesser amounts can sometimes suffice without theexercise of inventive skill).

Each component unit corresponding to multifunctional crosslinkingmonomer in a polymer chain serves as a branch point, from which a branchstructure can propagate. As the amount (given above) of multifunctionalcrosslinking monomer used in the polymerization reactions is increased,and thus the amount of corresponding component units in the copolymer isincreased, more branching occurs and the molecular weight of thehyperbranched copolymer is increased. It follows that the amount ofbranching can be regulated by altering the amount of multifunctionalcrosslinking monomer used in embodiments of the present invention while,as discussed hereinabove, the average size of the branches is controlledby altering the amount of chain transfer agent.

Paints and Other Coatings

The paints and other coatings of the invention are all essentiallyaqueous dispersions of polymeric materials containing one or morepigments to achieve a desired color, and (optionally) additions tofacilitate pigment dispersion, good rheology, and other desiredfeatures. Of course, the scope and nature of aqueous latex paints forboth architectural and industrial use, indoors and outdoors, arefamiliar to and well understood by those of skill in the art. However,our invention applies not only to such paints, but also to other aqueousdispersions referred to as water-borne coatings. These can bearchitectural or industrial stains, industrial maintenance coatings andthe like. The paints and other coatings we have invented can be utilizedin decorative, architectural, industrial and other conventionalapplications. Irrespective of the use to which they are put, ourinnovative paints and other coatings have in common that they are allsubject to improvement through practice of the invention.

The aqueous latex paints and other water-borne coatings, including theresultant films, because they are made with colorant compositions of theinvention, contain copolymer surfactants as discussed previously. Thesepaints and coatings, along with aqueous dispersions such as tint bases,also contain surfactants and/or dispersants, and optionally one or morewater-dispersible polymers, one or more low number average molecularweight polymers (such as polyethylene glycol or polypropylene glycol)each with an average molecular weight below about 300-about 8,000Daltons, and one or more rheology modifiers, for instance thickeners,especially associative thickeners. (It goes almost without saying thatthe latex paint, other water-borne coating, tint base, film, etc.contain a film-forming latex binder component in amount sufficient forthe formation of a suitable paint film, its being understood that thefilm-forming binder latex in a film embodiment can be in the cured“film” state.)

The inventive paint or other water-borne coating, comprising a tint baseand a colorant composition of the invention, contains a copolymersurfactant which is compatible with a wide range of film-formingadditives conventionally incorporated in latex paints and water-bornecoatings, as specified hereinbefore. When so incorporated, the copolymersurfactants cause the water-based paint or other water-borne coating toexhibit appropriate low or middle shear viscosity with improved flow andleveling. The ordinarily skilled worker, equipped with the teachingsherein, will be able to determine, as a matter of routine investigation,and without undue experimentation, amounts of copolymer surfactant whichare effective to confer appropriate low or middle shear viscosity withimproved flow and leveling on the paint or other coating. In certaingood embodiments of the invention, the amount of copolymer incorporatedin the paint or other coating is from 0.1 to 20, preferably from 1 to 15and more preferably from 2 to 10, weight % based on the total amount ofpolymer solids in the paint or other coating.

The copolymer surfactant utilized in practicing the invention iscompatible with the fill range of film-forming polymers conventionallyutilized in the coating field. Examples of film-forming emulsionpolymers which are suitable for use in the invention are acrylic, vinyl,polyvinyl acetate, vinyl acrylic, styrenic, and styrenated acrylicpolymers, among others. The film-forming polymer varies by the intendedapplication and a person of ordinary skill in the art will be able todetermine, as a matter of routine testing and without underexperimentation, which film-forming polymer to use for a particularapplication. When combined as a part of a colorant composition withfilm-forming polymer(s) in a tint base, or other aqueous dispersion, thecopolymer surfactant causes the tint base/colorant compositioncombination to exhibit desired low or middle shear viscosity (Krebunits—unit amounts depending upon the desired characteristics of aparticular formulation) with improved flow and leveling.

Once in possession of the teachings herein, those of ordinary skill inthe art will be able to determine, as a matter of routine testing andwithout under experimentation, amounts of copolymer surfactant which areeffective to confer appropriate low or middle shear viscosity withimproved flow and leveling on the tint base or other aqueous dispersion.In certain good embodiments of the invention, the amount of copolymersurfactant incorporated in the tint base or other aqueous dispersion isfrom 0.1 to 25, preferably from 1 to 20, and more preferably from 2 to15 weight % based on the total amount of polymer solids in the tint baseor other aqueous dispersion.

Methods

The method of forming a colorant composition in accordance with theinvention preferably comprises combining the components water, at leastone pigment and a copolymer surfactant, the copolymer surfactantcomprising moieties corresponding to the following monomers

-   -   (a) from about 10% to about 80% by weight of at least one C₃-C₁₂        α,β-ethylenically unsaturated carboxylic acid or anhydride,    -   (b) from about 10% to about 80% by weight of at least one C₃-C₁₂        α,β-ethylenically unsaturated vinyl monomer, and    -   (c) from about 0.01% to about 20% by weight of at least one        surfactant monomer, wherein each said surfactant monomer is        either an acrylic or methacrylic ester moiety joined with a        hydrophobic moiety by a bridging group consisting essentially of        a poly(ethyleneoxy) moiety, to form a colorant composition which        is not itself an aqueous latex paint or other water-borne        coating, which colorant composition is capable of mitigating any        change in the Stormer low-shear viscosity of an aqueous latex        paint or other water-borne coating formed of a mixture        comprising said composition and a tint base, such that said        Stormer low-shear viscosity of said paint or coating is not        substantially changed compared with the Stormer low-shear        viscosity of the tint base, and in which colorant composition        any VNCs are present in an amount no greater than 1000 ppm by        weight, any APEs or derivatives thereof are present in an amount        no greater than 1000 ppm by weight, any crystalline silica is        present in an amount no greater than 100 ppm by weight, and any        formaldehyde is present in an amount no greater than 10 ppm by        weight.

The method of forming an aqueous latex paint or other water-bornecoating in accordance with the invention preferably comprises mixing atint base as previously described, with a colorant compositioncontaining at least one pigment, water and a copolymer surfactant, whichcopolymer surfactant comprises moieties corresponding to the followingmonomers:

(a) from about 10% to about 80% by weight of at least one C₃-C₁₂α,β-ethylenically unsaturated carboxylic acid or anhydride,

(b) from about 10% to about 80% by weight of at least one C₂-C₁₂α,β-ethylenically unsaturated vinyl monomer, and

(c) from about 0.01% to about 20% by weight of at least one surfactantmonomer, wherein each said surfactant monomer is either an acrylic ormethacrylic ester moiety joined with a hydrophobic moiety by a bridginggroup consisting essentially of a poly(ethyleneoxy) moiety, the Stormerlow-shear viscosity of said paint or other water-borne coating, itsformation by mixing of the colorant composition with the tint basenotwithstanding, being not substantially changed compared with theStormer low-shear viscosity of the tint base, and in which paint orother coating any volatile organic compounds are present in an amount nogreater than 500 ppm by weight, any alkylphenol ethoxylates are presentin an amount no greater than 300 ppm by weight, any crystalline silicais present in an amount no greater than 100 ppm by weight, and anyformaldehyde is present in an amount no greater than 10 ppm by weight.

EXAMPLES

The following examples further illustrate certain embodiments of thepresent invention. These examples are provided solely for illustrativepurposes and in no way limit the scope of the present invention. It isnoted that, because of rounding, the sum of the amounts of eachingredient present may not equal the total in every case.

Examples 1-3 are directed to preparation of APE-free copolymersurfactants utilizing the basic procedures and conditions reported inthe Examples 1-8 of U.S. Pat. No. 7,402,627 which is hereby incorporatedby reference in its entirety.

Example 1 Preparation of Copolymer Surfactant Free of APE

The emulsion polymerization was carried out in a four-neck flask undernitrogen purge. The reaction flask was equipped with a condenser, athermometer, an agitator and a feeding pump. The flask was immersed in atemperature controlled water bath maintained at a constant temperaturewithin about ±0.1° C. of the set point. Table 1 shows the ingredientsused for the copolymer surfactant.

TABLE 1 Ingredients for Preparation of Copolymer Surfactant (1)Component Parts (by weight) Initial Charge in Reactor Deionized water48.5 Sodium dodecyl benzene sulfonate (22% w/w) 0.3 Monomer EmulsionDeionized water 17.3 Sodium dodecyl benzene sulfonate (22%) 0.7Methacrylic acid 11.6 Vinyl acetate 13.9 Butyl acrylate 4.2Tristyrlphenylpoly(ethyleneoxy)methacrylate (60%) 0.4 Diallyl phthalate0.03 Initiator Solution 1 Sodium persulfate 0.15 Deionized water 1.4Initiator Solution 2 Sodium persulfate 0.15 Deionized water 1.4 Total100

Deionized water and sodium dodecyl benzene sultanate (22% w/w) obtainedfrom Rhodia Inc. (Cranbury, N.J.) were charged into the reaction flaskand its contents were heated to 80° C. At 80° C., about 6% of monomeremulsion was charged into the reaction flask and held for 5 minutes.Thereafter, initiator solution 1 was charged into the reaction flask andheld for 15 minutes. Initiator solution 2 and the remaining monomeremulsion were then fed into the reaction flask over a period of fromabout 3 to about 4.5 hours. After feeding was complete, the temperatureof the reaction flask was maintained at 80-85° C. for one hour afterwhich it was cooled to about 25° C., and the copolymer surfactantproduct, in the form of a latex or emulsion, was recovered, with asolids content of about 30%.

This copolymer surfactant contained a hydrophobe surfactant monomer,tristyrylphenylpoly(ethyleneoxy)methacrylate, and a crosslinkingmonomer, diallyl phthalate.

Example 2 Preparation of Copolymer Surfactant (2)

The reactant composition was the same as in Example 3 of U.S. Pat. No.7,402,627, except ammonium nonylphenyl ether persulfate, an APEsurfactant, was replaced with an APE-free surfactant, sodium tridecylethoxy sulfate (RHODAPEX EST-30 from Rhodia Inc.), as shown in Table 2.

The same procedures and conditions as in Example 1 were used.

TABLE 2 Ingredients for Preparation of Copolymer Surfactant (2)Component Parts (by weight) Initial Charge in Reactor Deionized water49.4 Sodium tridecyl ethoxy sulfate (30% w/w) 0.1 Monomer EmulsionDeionized water 13.9 Sodium tridecyl ethoxy sulfate (30%) 0.8 Abex 20201.2 Methacrylic acid 9.8 Vinyl acetate 9.8 Ethyl methacrylate 9.8Tristyrlphenylpoly(ethyleneoxy) methacrylate (60%) 1 Initiator Solution1 Ammonium persulfate 0.03 Deionized water 1.3 Initiator Solution 2Deionized water 2 Sodium tridecyl ethoxy sulfate (30%) 0.5 Abex 2020 0.4Ammonium persulfate 0.04 Rinse Deionized water 0.9 Total 100

The surfactant ABEX 2020 was a proprietary formulation obtained fromRhodia Inc. It is believed to comprise a mixture of an anionicsurfactant and a nonionic surfactant. The copolymer surfactant product,in the form of a latex or emulsion, was recovered, with a solids contentof about 30%.

Example 3 Preparation of Copolymer Surfactant Free of APE

The monomer composition was the same as in Example 4 of U.S. Pat. No.7,402,627, except a di-functional monomer, diacrylate (Sartomer SR610),was used as a crosslinking monomer. Ammonium nonylphenyl etherpersulfate (APE surfactant) and Abex 2020, per Example 4 of U.S. Pat.No. 7,402,627, were replaced with sodium dodecyl benzene sulfonate (22%w/w) and RHODAFAC RS-610A-25 (polyoxyethylene tridecyl etherphosphate,Rhodia Inc.).

The same procedures and conditions as for Example 1 were used inpreparing the copolymer surfactant. Thus, after monomer feeding wascomplete, the temperature of the reaction flask was maintained at 80-85°C. for one hour. The reactor was then cooled to 60-65° C. and chasermixtures were fed to the reactor over 30 minutes. It was then cooled toroom temperature. The copolymer surfactant product, in the form of alatex or emulsion, was recovered, with a solids content of about 30%.

TABLE 3 Ingredients for Preparation of Copolymer Surfactant (3)Component Parts (by weight) Initial Charge in Reactor Deionized water47.6 Sodium dodecyl benzene sulfate (22%) 0.1 Monomer Emulsion Deionizedwater 13.5 Sodium dodecyl benzene sulfate (22%) 1.2 RHODAFAC RS-610A-251.0 Methacrylic acid 9.33 Vinyl acetate 9.33 Ethyl methacrylate 9.33Behenylpoly(ethyleneoxy) methacrylate (50%) 2.4 Diacrylate (SR610) 0.3Initiator Solution 1 Ammonium persulfate 0.03 Deionized water 1.3Initiator Solution 2 Deionized water 1.9 Sodium dodecyl benzene sulfate(22%) 0.6 RHODAFAC RS-610A-25 0.4 Ammonium persulfate 0.04 RinseDeionized water 0.9 Chaser Solution Oxidizing solution Deionized water0.4 t-butylperoxide 0.06 Reducing Solution Deionized water 0.4BRUGGOLITE FF{circumflex over ( )}M (Bruggmann Chem.) 0.04 Rinsedeionized water 0.7 Total 100

The copolymer of Example 3 contains a hydrophobe monomer of behenylpoly(ethyleneoxy)methacrylate.

Example 4 Colorant Composition Containing a Red Oxide Pigment

A colorant composition comprising a red oxide pigment and a copolymersurfactant of Example 2 was prepared. Table 4 shows the ingredients usedin the red oxide colorant composition.

The colorant composition was prepared as follows. To a 1 L stainlesssteel beaker, equipped with a stirrer that stirred under slow agitationat about 500 rpm, was added in the following order: water, copolymersurfactant emulsion from Example 2 and sodium hydroxide solution. Whenthe solution became clear, the remaining ingredients were added in theorder set forth in Table 4 (top to bottom), and mixing continued atabout 500 rpm for 10 minutes. The mixing speed was increased to about2,500 rpm and mixing continued for about 45 minutes at that speed untilthe mixture appeared to be a homogenous dispersion. Carbowax PEG 400 isa solvent of polyethylene glycol with a number average molecular weightof about 400 Daltons. It does not contain VNCs. Proxel BZ Plus is apreservative free from formaldehyde from Arch Chemical. BYK-155 is anon-APE dispersant from BYK Chemie. Tego Dispers 750W is an APE-freedispersant from Evonik Inc.

The red oxide color composition did not contain APEs, formaldehyde andcrystalline silica. It did not contain appreciable VOC amounts, butrather had a very low VOC content of 82 ppm, mostly from impurities dueto additives.

TABLE 4 Ingredients for Preparation of Colorant Composition of Red OxideComponent Parts (by weight) Water 427 APE free copolymer surfactant ofExample 2 25 Sodium hydroxide 50% (W/W) 4.5 Carbowax PEG 400 80 PROXELBZ PLUS (preservative) 2.5 BYK-155 (dispersant, BYK Chemie) 80 TEGODISPERS 750W (dispersant) 30 Red oxide R-2199D (Rockwood) 800 HI-MARDFC-10 Deformer 10.7 Styrene acrylic latex (45%) 50 Total 1509

Example 5 Colorant Composition of Organic Yellow Pigment

A colorant composition comprising an organic yellow pigment and acopolymer surfactant of Example 2 was prepared. It was made withingredients free of APEs, formaldehyde, and crystalline silica. It didnot contain appreciable VOC amounts. The colorant composition wasprepared with the same procedures for grinding as in Example 4. Aftergrinding at 2500 rpm for 45 minutes, the mixture was then processedthrough a sand mill (Model L-3-J, Chicago Boiler Co., Buffalo Grove,Ill.) using 1.00 mm diameter glass beads as the grinding media.

Example 6 Colorant Composition of Organic Green Pigment

A colorant composition comprising an organic green pigment and acopolymer surfactant of Example 2 was prepared. It was made withingredients free of APEs, formaldehyde and crystalline silica. It didnot contain appreciable VOC amounts. The colorant was prepared accordingto the same procedures as in Example 5.

Example 7 Colorant Composition of Organic Blue Pigment

A colorant composition comprising an organic blue pigment and acopolymer surfactant of Example 2 was prepared. It was made withingredients free of APEs, formaldehyde and crystalline silica. It didnot contain appreciable VOC amounts. The colorant was prepared accordingto the same procedures as in Example 5.

Example 8 VOC-Content of Colorant Compositions for Examples 4-7

Preliminarily, VOCs were measured by headspace Gas Chromatography/MassSpectroscopy. This test method is for determining the weight amount ofindividual VNCs in an aqueous latex paint or other water-borne coating.It can be conducted using a commercially available capillary gaschromatograph equipped with a mass selectivity detector and programmingcapability (electronic flow control is helpful). Here, an Agilent 6890 Ngas chromatograph, an Agilent 5973 mass selectivity detector, and anAgilent 7694E headspace sampler were utilized. Standard instrumentconditions for testing were

Detector Mass Selectivity Column 100% polyethylene glycol (PhenomenexZB- Wax), 30 meters length, 0.25 mm I.D., 0.25 μm film thickness CarrierGas Helium Pressure 13.3 Flow Rate 1.0 mL per min. constant flow (38cm/s) Split Ratio 50 Split Flow 49.9 Total Flow 53.5 Inlet Temp. 270° C.Detector Temp. 280° C. MS Source Temp. 230° C. MS Quad Temp. 150° C. GCOven Parameters. 50° C. initial. Hold @ 50° C. for 1 minute then ramp to250° C. @ 15° C./minute. Hold @ 250° C. for 15 minutes. Headspace VialSize 10 mL Headspace Sample 0.0500 ± 0.0010 g Size Headspace Temp. 120°C. equilibrated for 15 minutes Transfer Line Temp. 140° C. Loop Temp.130° C.Ultra high purity grade carrier gas was employed along with reagentgrade chemicals.

The test protocol is as follows: 50 ppm of each target substance fordetermination is added to each of two aliquots of the material to beanalyzed (e.g., aqueous latex paint or colorant composition). Then, thetarget substance(s) are diluted to 25 ppm in one of the aliquots byadding to it a further and equal amount of the material to be analyzed.Thereafter, into a 10 mL headspace vial is introduced a 0.0500±0.0010 gamount of the material to be analyzed; into a separate 10 mL headspacevial is introduced a 0.0500±0.0010 g amount of such material along withthe added target substance(s) at the 50 ppm concentration, and into yetanother 10 mL headspace vial a 0.0500±0.0010 g amount of such materialwith added target substance(s) at the 25 ppm concentration. If there arenumerous target substances, a plurality of headspace vials may be filledeach with a 10 mL sample that contains a different (though notnecessarily mutually exclusive) sub-group of target substances vis-à-visthe other samples (for each said sub-group there being one vial ofmaterial at the 50 ppm additive level, and another of material at the 25ppm level). The target substances in the samples are separated via gaschromatography as mentioned previously; in conjunction with theforegoing, the characteristic mass of each targeted substance isidentified and integrated, and approximate retention times andcharacteristic masses ascertained.

The area corresponding to target substance is divided by the areaderived in an analogous determination corresponding to an internalstandard (e.g., cyclohexane) to arrive at a response factor. Plottingresponse factor against added amount of the target substance on aCartesian coordinate grid yields the amount of a targeted substance inthe unknown sample, corresponding to the x-intercept of the plot.

The results are set forth in terms of parts of VOC per million parts oftotal sample (ppm) and percent by weight, and are presented in Table 5.

Example 9A Comparative Examples VOC-Content of Commercial ColorCompositions

The VOC contents of the following commercial low-VOC andethylene-glycol-containing color compositions were measured using themethod in Example 8 above (note: “VOC” refers to “volatile organiccompounds” and is a more specific sub-group of VNC). The results are setforth in Table 5:

TABLE 5 VOC of Colorants VOC % by Colorants (ppm) weight ExperimentalLow VOC Colorants A Red Oxide of Example 4 82 0.0082 Organic yellow ofExample 5 292 0.0292 Organic green of Example 6 147 0.0147 Organic blueof Example 7 188 0.0188 Commercial Low VOC Colorants B Red Oxide 2670.0267 Organic yellow 114 0.0114 Organic green 362 0.0362 Organic blue119 0.0119 Commerical Low VOC Colorants C Red Oxide 570 0.0570 Organicyellow 1163 0.1163 Organic green 2626 0.2626 Organic blue 530 0.0530Commercial Low VOC Colorants D Red Oxide 92 0.0092 Organic yellow 23380.2338 Organic green 500 0.0500 Organic blue 797 0.0797 Commercial LowVOC Colorants E Red Oxide 474 0.0474 Organic yellow 523 0.0523 Organicgreen 999 0.0999 Organic blue 440 0.0440 Commercial Normal VOC ColorantsF Red Oxide 208000 20.8% Organic yellow 104000 10.4% Organic green311000 31.1% Organic blue 304000 30.4%

Four commercial low VOC colorants were obtained and used for testing,labeled B, C, D and E. In addition, 1 regular commercial colorant(normal higher VOC) was also tested and labeled F. These colorants weretested using a Headspace GC at 120° C. for VOC's. The results werelisted on Table 5 verses the experimental colorants.

Example 9B

A further analysis of VOC levels was carried out among a low-VOC tintbase (Sample A), a phthalo-green-tinted aqueous latex paint of ourinvention (Sample B), various competitive low-VOC aqueous latex-paints(Samples C-E), and a competitive normal-VOC aqueous latex paint (SampleF). The aqueous latex-paints tested were prepared by adding a variety ofgreen colorants to the same low-VOC tint base. The Sample B paint andcorresponding colorant composition were prepared generally in accordancewith the preceding disclosure of our invention. Following Table 6details the VOC-level results obtained in testing the respective Samplespursuant to the Headspace Method described:

TABLE 6 Headspace Comparison of Phthalo Green Tints Sample A Sample BSample C Sample D Sample E Sample F Base (Lot 942914) Low VOC Low VOCLow VOC Low VOC Low VOC Low VOC Eggshell Eggshell Eggshell EggshellEggshell Eggshell Tint None Experimental Competitive CompetitiveCompetitive Competitive A B C D Normal Low VOC Low VOC Low VOC Low VOCVOC Colorant Colorant Colorant Colorant Colorant t-Butyl Alcohol 113 8484 81 76 64 Isopropyl Alcohol — — — — — n-Butyl Ether 5 27 22 4 24 3Butyl Propionate 11 10 12 11 8 — Xylene(s) — 1 — 2 — 24 (2) AliphaticBlends(s)⁻¹ — — — — 88 (8) Butyl Alcohol 110 95 93 87 85 87 PropyleneGlycol⁻¹ — — — — 27 Ethylene Glycol 53 24 34 47 33 4,219 Dodecanol — 1310 8 17 Texanol ® — — 29 — — Unknown(s)⁻² — 5 (2) — 8 4 (2) — Total(ppm) 292 246 258 279 234 4,529 ⁻¹Quantified as toluene ⁻²Match qualityunder 70%, quantified as toluene

The results with a paint and colorant composition according to ourinvention are comparable to those with other low-VOC products, and muchbetter than those with the normal-VOC product.

Example 10 Rheology of Paints Tinted with Colorant Compositions ofExamples 4-7

The rheology of tint base paints, as indicated by properties such asviscosity, leveling, and sag resistance, is important to properapplication and dry film appearance. Unfavorable rheology properties,such as low Stormer viscosity and low sag resistance, may lead todripping or sagging when the paint is applied to a substrate. Poorleveling properties may result in brush marks.

The colorants of Examples 4-7 were individually added to a Low-VOCCommercial Matte Pastel Paint Tint Base, a Low-VOC Commercial Matte DeepTint Base, and a Low-VOC Commercial Semigloss Deep Tint Base. Pastelbases had added to them 6 ounces of colorants, and deep bases had addedto them 18 ounces of colorants. The paints were shaken with a mechanicalshaker for 6 minutes for thorough mixing of the bases and colorantcompositions.

The Stormer Viscosity in Krebs Units (KU) was determined according toASTM Standard D562-01, “Standard Test Method for Consistency of PaintsMeasuring Krebs Unit (KU) Viscosity Using a Stormer-Type Viscometer,”using a Brookfield Viscometer model KU-1 obtained from BYK-Gardner USA(Rivers Park II. Md.). The Stormer viscosity was measured at 25° C.

The change of KU upon adding of the colorants of Examples 4-7 is listedin Table 7. Satisfactory KU changes in a pastel base would typically beless 5 and in deep bases would typically be less than 10.

The leveling of paints was determined from draw-downs according to ASTMStandard D4062-99, “Standard Test Method for Leveling of Paints byDraw-Down Method.” A Leneta Leveling Test Blade (LTB-2) and LenetaDraw-Down Charts (Form 18B), each obtained from the Leneta Company(Mahwah, N.J.), were used for these tests. The draw-downs were evaluatedvisually and assigned a rating of from 1 to 10 in comparison to a set ofstandards, as specified in ASTM D4062.

The leveling ratings of paints tinted with the colorants of Examples 4-7are listed in Table 7. A leveling rating of 9 or greater is consideredto be excellent.

Sag resistance was determined from Leneta draw-downs using a Lenetaanti-sag meter. The paint was drawn down on a draw-down card positionedhorizontally on a vacuum metal plate. The chart was then immediatelyplaced in a vertical position with the paint stripes horizontal and leftedge (thinnest stripe) at the top, and allowed to dry. Each stripe,ranging in wet film thickness from 3 to 12 mils, is considered as havingthe same rating number as the notch by which it has been applied. Thehighest number (thickest) stripe that does not touch the one belowitself is referred to as the index stripe, and its number is theAnti-Sag index of the paint. The Sag resistance index values of paintstinted with the colorants of Examples 4-7 are listed in Table 7.

Example 11 Comparative Examples of Rheology of Tint-Base Paints withCommercial Colorants

A Low-VOC Commercial Matte Pastel Paint Tint Base Matte Deep Tint Base,and A Low-VOC Commercial Semigloss Deep Tint. Base were tinted with thecolorants of Example 9A. The same amounts of colorants were added to thebases as in Example 10.

Stormer Viscosity change, leveling of paints, and sag resistance weredetermined with the same methods as in Example 10. The results arelisted in Table 7.

TABLE 7 Stormer viscosity change (ΔKU), leveling, sag resistance ofpaints tinted with colorants Matte Pastel Base Matte Deep Base SemiglossDeep Base Colorants ΔKU Leveling Sag ΔKU Leveling Sag ΔKU Leveling SagRed oxide of Example 4 −5 9 12 −4 10 12 −2 10 11 Org. Yellow of Example5 +2 9 10 −7 10 8 −4 10 8 Org. Green of Example 6 −2 9 12 −8 10 12 −1 1012 Org. Blue of Example 7 0 9 12 0 8 12 4 9 12 Comparative Examples Redoxide B −14 9 12 −27 10 7 −20 10 6 Org. Yellow of B −14 9 12 −27 10 7−23 10 6 Org. Green of B −15 9 12 −27 10 7 −22 10 7 Org. Blue of B −13 912 −26 10 8 −22 10 8 Red oxide of C −12 9 12 −35 10 7 −27 10 7 Org.Yellow of C −15 9 12 −34 10 4 −28 10 7 Org. Green of C −12 9 12 −23 9 7−22 10 5 Org. Blue of C −12 9 12 −27 9 7 −23 10 7 Red oxide of D −21 911 −42 9 6 −36 10 6 Org. Yellow of D −20 9 10 −37 10 6 −31 10 6 Org.Green of D −21 9 10 −37 9 5 −33 10 5 Org. Blue of D −26 9 10 −44 10 6−39 9 6 Red oxide of E −49 10 6 Org. Yellow of E −19 9 9 −43 10 5 −36 106 Org. Green of E −13 10 −21 90 7 −20 10 7 Org. Blue of E −4 9 12 −3 1012 −2 10 12 Red oxide of F −14 9 10 −27 10 4 −20 10 4 Org. yellow of F−26 9 9 −48 10 4 −42 10 3 Org. green of F −30 9 8 −50 10 4 −42 10 3 Org.blue of F −24 9 9 −43 10 5 −41 10 5

Table 7 shows that colorants of Example 4-7 gave the least change in KUas compared to all other commercial colorants described in Example 9A,and have excellent leveling and sag resistance.

The comparative examples carried out with commercial colorantsdemonstrated significant decrease in KU in both pastel and deep bases,and a drop in sag in deep bases. Although the leveling properties in thecomparative examples may have been good, that was due to much lowerviscosity of the tinted paints.

Despite formulation to meet rigorous environmental sensitivities, theresults with a paint and colorant composition according to our inventionwere either better than or at least comparable to other low- ornormal-VOC products for each of the properties tested. This uniformexcellence characterizing the invention was superior to the performancecontour of the comparative products which in each case fell short inrespect of at least one property.

Example 12 Water Sensitivity, Color Transfer and Gloss of Tinted Paintsin Example 10

Water sensitivity and gloss were measured on 3-mil draw downs dried forone day.

Water sensitivity was tested with a few drops of water on the paintsurface for a minute. The water was wiped off and wetted surface wasscratched with finger nails to check the hardness of the film. Therating is from 1 to 5, with 5 being the hardest film, indicating itsbeing least water sensitive.

Gloss was measured on Commercial Semigloss deep tint bases with a BYKgloss meter at 65 degrees.

Color transfer (or color rub-off) for paints tinted with colorants ofred oxide and organic blue were measured on 3-mil draw downs dried for 7days. A rating of 1 to 5 was assigned, with 5 being the best resistanceto color transfer.

The results of water sensitivity, color transfer and gloss are listed inTable 8.

Example 13 Comparative Examples of Water Sensitivity, Color Transfer andGloss

Water sensitivity, color transfer and gloss were measured with the samemethods as in Example 12 for paints tinted with commercial colorants inExample 11. The results are listed in Table 8.

TABLE 8 Water Sensitivity, Color Transfer and Gloss Commercial MatteCommercial Deep Base Semigloss Deep Base Water Color Water ColorColorants Sensitivity transfer Sensitivity transfer Gloss Red oxide of 43 1 5 54 Example 4 Org. Yellow of 3.5 5 64 Example 5 Org. Green of 3 4.562 Example 6 Org. Blue of 4.5 3.5 5 5 62 Example 7 Red oxide of B 1 1 12 58 Org. Yellow of B 4 1 57 Org. Green of B 1 2 60 Org. Blue of B 1.5 21 2 59 Red oxide of C 4 1 1 4.5 59 Org. Yellow of C 1.5 3 57 Org. Greenof C 1 1 65 Org. Blue of C 3.5 2 4 3 60 Red oxide of D 2 1 4 4.5 53 Org.Yellow of D 1 1 39 Org. Green of D 1 1 41 Org. Blue of D 1 3 1 2 47 Redoxide of E 3.5 4 n/a n/a n/a Org. Yellow of E 4.5 5 65 Org. Green of E4.5 4 63 Org. Blue of E 5 3 5 4.5 60 Red oxide of F 3 3 1 4.5 45 Org.yellow of F 4 1 48 Org. green of F 4 1 41 Org. blue of F 4.5 2 1 2 45

As previously, the tabulated results show that, in contrast to theinvention's uniform excellence, the performance contour of thecomparative products in each case was no better than comparable to thatof the invention. Since, when also taking into account the otherproperties assessed in preceding Examples, the comparative products allfall short in respect of at least one property, the invention isdemonstrated to be superior.

The embodiments described herein are illustrative but not limiting inrespect of the invention, and are not intended to exclude equivalentsthereof, or to constrain the claims unduly.

1-45. (canceled)
 46. A colorant composition suitable as a precursor toan aqueous latex paint or other water-borne coating, which colorantcomposition comprises at least one color pigment, water, and a copolymersurfactant, which colorant composition is not itself an aqueous latexpaint or other water-borne coating, wherein the copolymer surfactantcomprises moieties corresponding to the following monomers: (a) fromabout 10% to about 80% by weight of at least one C₃-C₁₂□□□□-ethylenically unsaturated carboxylic acid or anhydride, (b) fromabout 10% to about 80% by weight of at least one C₂-C₁₂□□□□-ethylenically unsaturated vinyl monomer, and (c) from about 0.01%to about 20% by weight of at least one surfactant monomer, wherein saidsurfactant monomer is either an acrylic or methacrylic ester moietyjoined with a hydrophobic moiety by a bridging group comprising apoly(ethyleneoxy) moiety, and wherein the copolymer surfactant isattached to the at least one color pigment to form a plurality of colorpigment composite particles.
 47. The colorant composition of claim 46,wherein the hydrophobic moiety comprises a styrylphenyl moiety, an alkylmoiety or an alkylphenyl moiety.
 48. The colorant composition of claim46, wherein any volatile non-aqueous constituents are present in anamount no greater than 1000 ppm by weight, any alkylphenol ethoxylatesand derivatives thereof are present in an amount no greater than 1000ppm by weight, any crystalline silica is present in an amount no greaterthan 100 ppm by weight, and any formaldehyde is present in an amount nogreater than 10 ppm by weight.
 49. The colorant composition of claim 48,wherein any volatile non-aqueous constitutients are present in an amountno greater than 500 ppm by weight, any alkylphenol ethoxylates andderivatives thereof are present in an amount greater than 100 ppm byweight, any crystalline silica is present in an amount no greater than100 ppm by weight, and any formaldehyde is present in an amount nogreater than 5 ppm by weight,
 50. The colorant composition of claim 49,wherein any volatile non-aqueous constituents are present in an amountno greater than 300 ppm by weight, any alkylphenol ethoxylates andderivatives thereof are present in an amount no greater than 300 ppm byweight, any crystalline silica is present in an amount no greater than 5ppm by weight, and any formaldehyde is present in an amount no greaterthan 5 ppm by weight.
 51. The colorant composition of claim 46, whereinsaid colorant composition is substantially entirely free of any volatilenon-aqueous constituents, of any alkylphenol ethoxylates and derivativesthereof, of any crystalline silica and of any formaldehyde.
 52. Thecolorant composition of claim 46, which comprises at least one organicpigment, at least one inorganic pigment, or at least one organic pigmentand at least one inorganic pigment.
 53. The colorant composition ofclaim 46, further comprising at least one additional surfactant which isdifferent from said copolymer surfactant.
 54. The colorant compositionof claim 46, further comprising a water-soluble polymer selected fromthe group consisting of polycarboxylic acids, copolymers comprising amonomer containing a carboxylic acid, alkali soluble emulsion polymers,cellulose derivatives, salts of a polyacrylic acid, salts of a copolymercomprising a monomer containing an acrylic acid, polyvinylpyrrolidone,copolymers comprising vinylpyrrolidone monomer, and two or more thereof.55. The colorant composition of claim 1, wherein the copolymersurfactant comprises moieties corresponding to the following monomers(a) from about 10% to about 80% by weight of methacrylic or acrylicacid, (b) from about 10% to about 80% by weight of a first vinyl esterwhich is alkyl methacrylate, the alkyl of which is of from 2 to 12carbon atoms, and a second vinyl ester selected from the groupconsisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinylisobutyrate, vinyl benzoate, vinyl m-chlorobenzoate, vinylp-methoxybenzoate, and vinyl alpha-chloroacetate, and (c) from about0.01% to about 20% by weight of at least one surfactant monomer, whereinsaid surfactant monomer is either an acrylic or methacrylic ester moietyjoined with a hydrophobic moiety which is a styrylphenyl moiety by abridging group consisting essentially of a poly(ethyleneoxy)moiety. 56.The colorant composition of claim 46, wherein each said surfactantmonomer is either an acrylic or methacrylic ester moiety joined with ahydrophobic moiety selected from the group consisting ofmonostyrylphenyl, distyrylphenyl, tristyrylphenyl or a mixture thereofby a bridging group comprising a poly(ethyleneoxy) moiety.
 57. Thecolorant composition of claim 46, wherein the poly(ethyleneoxy) moietycomprises from about 10 to about 40 ethyleneoxy units.
 58. The colorantcomposition of claim 46, wherein either the hydrophobic moiety or thehydrophilic moiety provides the attachment to the at least one colorpigment.